diff --git a/man/signal-cli-dbus.5.adoc b/man/signal-cli-dbus.5.adoc
index 60ffa64a..26f66aba 100755
--- a/man/signal-cli-dbus.5.adoc
+++ b/man/signal-cli-dbus.5.adoc
@@ -45,21 +45,22 @@ Phone numbers always have the format +<countrycode><regional number>
 
 updateGroup(groupId<ay>, name<s>, addMembers<as>, avatar<s>) -> groupId<ay>::
 updateGroup(base64GroupId<s>, name<s>, addMembers<as>, avatar<s>) -> base64GroupId<s>::
+updateGroup(groupId<ay>, name<s>, description<s>, addMembers<s>, removeMembers<s>, addAdmins<s>, removeAdmins<s>, resetGroupLink<b>, groupLinkState<s>, addMemberPermission<s>, editDetailsPermission<s>, avatar<s> expiration<i>) -> groupId<ay>::
 updateGroup(base64GroupId<s>, name<s>, description<s>, addMembers<s>, removeMembers<s>, addAdmins<s>, removeAdmins<s>, resetGroupLink<b>, groupLinkState<s>, addMemberPermission<s>, editDetailsPermission<s>, avatar<s> expiration<i>) -> base64GroupId<s>::
-* groupId               : Byte array representing the internal group identifier
-* base64GroupId         : String representing the internal group identifier in Base64 format
+* groupId               : Byte array representing the internal group identifier (create new group if null)
+* base64GroupId         : String representing the internal group identifier in Base64 format (create new group if empty)
 * name                  : Name of group (empty if unchanged)
 * description           : Description (empty if unchanged)
 * addMembers            : String array of new members to be invited to group (empty if unchanged)
 * removeMembers         : String array of members to be removed from group (empty if unchanged)
 * addAdmins             : String array of members granted admin privileges (empty if unchanged)
 * removeAdmins          : String array of members denied admin privileges (empty if unchanged)
-* resetGroupLink        : Boolean (true = change the group link, false or empty = don't change)
+* resetGroupLink        : Boolean (true = change the group link, false = don't change)
 * groupLinkState        : String ("enabled", "enabled-with-approval", "disabled") (empty if unchanged)
 * addMemberPermission   : String of who may add members ("every-member", "only-admins") (empty if unchanged)
 * editDetailsPermission : String of who may edit group details ("every-member", "only-admins") (empty if unchanged)
 * avatar                : Filename of avatar picture to be set for group (send the name of an empty file to delete avatar; leave field empty if avatar is unchanged)
-* expiration            : Expiration time for messages sent to this number (in seconds). Set to 0 to disable. (empty if unchanged)
+* expiration            : Expiration time for messages sent to this group (in seconds). Set to 0 to disable. (empty if unchanged)
 
 Exceptions: AttachmentInvalid, Failure, InvalidNumber, GroupNotFound
 
@@ -93,8 +94,8 @@ Messages from blocked groups will no longer be forwarded via DBus.
 
 Exceptions: GroupNotFound
 
-joinGroup(inviteURI<s>) -> <>::
-* inviteURI : String starting with https://signal.group which is generated when you share a group link via Signal App
+joinGroup(inviteUri<s>) -> <>::
+* inviteUri : String starting with https://signal.group which is generated when you share a group link via Signal App
 
 Exceptions: Failure
 
@@ -113,7 +114,7 @@ isMember(base64GroupId<s>) -> active<b>::
 * base64GroupId : String representing the internal group identifier in Base64 format
 * active        : Boolean representing whether you are a member of the group
 
-Exceptions: None; returns false for a non-existing/unknown group
+Exceptions: GroupNotFound
 
 sendEndSessionMessage(recipients<as>) -> <>::
 * recipients : String array of phone numbers
@@ -209,9 +210,9 @@ Exception: Failure
 
 trust(number<s>, safetyNumber<s>) -> <>::
 * number       : Phone number
-* safetyNumber : Verify the safety number associated with the phone number. 
+* safetyNumber : Verify the safety number associated with the phone number.
 
-Exceptions: Failure, InvalidNumber;
+Exceptions: Failure, InvalidNumber
 
 sendTyping(typingAction<b>, base64GroupId<s>, recipients<as>) -> <>::
 * typingAction  : true = start typing, false = stop typing
@@ -263,15 +264,47 @@ groupName     : The display name of the group
 groupId       : Byte array representing the internal group identifier
 base64GroupId : String representing the internal group identifier in Base64 format
 
-Exceptions: None; if the group name is not found an empty string is returned
+Exception: Failure if base64GroupId or groupId is malformed; GroupNotFound
 
 getGroupMembers(groupId<ay>) -> members<as>::
 getGroupMembers(base64GroupId<s>) -> members<as>::
-members       : String array with the phone numbers of all active members of a group
-groupId       : Byte array representing the internal group identifier
-base64GroupId : String representing the internal group identifier in Base64 format
+* members       : String array with the phone numbers of all active members of a group
+* groupId       : Byte array representing the internal group identifier
+* base64GroupId : String representing the internal group identifier in Base64 format
 
-Exceptions: None; if the group name is not found an empty array is returned
+Exception: Failure if base64GroupId or groupId is malformed; GroupNotFound
+
+getGroupAdminMembers(groupId<ay>) -> adminMembers<as>::
+getGroupAdminMembers(base64GroupId<s>) -> adminMembers<as>::
+* groupId       : Byte array representing the internal group identifier
+* base64GroupId : String representing the internal group identifier in Base64 format
+* adminMembers  : String array of members granted admin privileges
+
+Exception: Failure if base64GroupId or groupId is malformed; GroupNotFound
+
+getGroupPendingMembers(groupId<ay>) -> pendingMembers<as>::
+getGroupPendingMembers(base64GroupId<s>) -> pendingMembers<as>::
+* groupId        : Byte array representing the internal group identifier
+* base64GroupId  : String representing the internal group identifier in Base64 format
+* pendingMembers : String array of pending members
+
+Exception: Failure if base64GroupId or groupId is malformed; GroupNotFound
+
+getGroupRequestingMembers(groupId<ay>) -> requestingMembers<as>::
+getGroupRequestingMembers(base64GroupId<s>) -> requestingMembers<as>::
+* groupId           : Byte array representing the internal group identifier
+* base64GroupId     : String representing the internal group identifier in Base64 format
+* requestingMembers : String array of requesting members (awaiting admin approval for membership)
+
+Exception: Failure if base64GroupId or groupId is malformed; GroupNotFound
+
+getGroupInviteUri(groupId<ay>) -> inviteUri<s>::
+getGroupInviteUri(base64GroupId<s>) -> inviteUri<s>::
+* groupId       : Byte array representing the internal group identifier
+* base64GroupId : String representing the internal group identifier in Base64 format
+* inviteUri     : String starting with https://signal.group which is generated when you share a group link via Signal App
+
+Exceptions: Failure if base64GroupId or groupId is malformed; GroupNotFound
 
 listNumbers() -> numbers<as>::
 numbers : String array of all known numbers
@@ -300,7 +333,7 @@ isGroupBlocked(base64GroupId<s>) -> state<b>::
 * base64GroupId : String representing the internal group identifier in Base64 format
 * state         : true=blocked, false=not blocked
 
-Exceptions: None; for unknown groups false is returned
+Exceptions: Failure if base64GroupId or groupId is malformed; GroupNotFound
 
 isRegistered(number<s>) -> result<b>::
 isRegistered(numbers<as>) -> results<ab>::
diff --git a/src/main/java/org/asamk/Signal.java b/src/main/java/org/asamk/Signal.java
index 36c08424..b025066e 100644
--- a/src/main/java/org/asamk/Signal.java
+++ b/src/main/java/org/asamk/Signal.java
@@ -86,7 +86,8 @@ public interface Signal extends DBusInterface {
 
     void trust(String number, String safetyNumber) throws Error.Failure, Error.InvalidNumber;
 
-    void sendTyping(boolean typingAction, String base64GroupId, List<String>recipients) throws Error.Failure, Error.UntrustedIdentity;
+    void sendTyping(boolean typingAction, String base64GroupId, List<String>recipients) throws Error.Failure, Error.UntrustedIdentity, Error.GroupNotFound;
+    void sendTyping(boolean typingAction, byte[] groupId, List<String>recipients) throws Error.Failure, Error.UntrustedIdentity, Error.GroupNotFound;
 
     String getContactName(String number) throws Error.InvalidNumber;
 
@@ -97,17 +98,56 @@ public interface Signal extends DBusInterface {
     void setContactBlocked(String number, boolean blocked) throws Error.InvalidNumber;
 
     void setGroupBlocked(byte[] groupId, boolean blocked) throws Error.GroupNotFound;
+    void setGroupBlocked(String base64GroupId, boolean blocked) throws Error.GroupNotFound;
 
     List<byte[]> getGroupIds();
+    // To get the group Ids in base 64 format, either use the getBaseGroupIds() method, or
+    //   the getGroupIds(dummy) form, where dummy represents any string
+    List<String> getBase64GroupIds();
+    List<String> getGroupIds(String dummy);
 
-    String getGroupName(byte[] groupId);
+    String getGroupName(byte[] groupId) throws Error.GroupNotFound, Error.Failure;
+    String getGroupName(String base64GroupId) throws Error.GroupNotFound, Error.Failure;
 
-    List<String> getGroupMembers(byte[] groupId);
+    List<String> getGroupMembers(byte[] groupId) throws Error.GroupNotFound, Error.Failure;
+    List<String> getGroupMembers(String base64GroupId) throws Error.GroupNotFound, Error.Failure;
+
+    List<String> getGroupAdminMembers(byte[] groupId) throws Error.GroupNotFound, Error.Failure;
+    List<String> getGroupAdminMembers(String base64GroupId) throws Error.GroupNotFound, Error.Failure;
+
+    List<String> getGroupPendingMembers(byte[] groupId) throws Error.GroupNotFound, Error.Failure;
+    List<String> getGroupPendingMembers(String base64GroupId) throws Error.GroupNotFound, Error.Failure;
+
+    List<String> getGroupRequestingMembers(byte[] groupId) throws Error.GroupNotFound, Error.Failure;
+    List<String> getGroupRequestingMembers(String base64GroupId) throws Error.GroupNotFound, Error.Failure;
+
+    String getGroupInviteUri(byte[] groupId) throws Error.GroupNotFound, Error.Failure;
+    String getGroupInviteUri(String base64GroupId) throws Error.GroupNotFound, Error.Failure;
 
     byte[] updateGroup(
             byte[] groupId, String name, List<String> members, String avatar
     ) throws Error.AttachmentInvalid, Error.Failure, Error.InvalidNumber, Error.GroupNotFound;
 
+    String updateGroup(
+            String base64GroupId, String name, List<String> members, String avatar
+    ) throws Error.AttachmentInvalid, Error.Failure, Error.InvalidNumber, Error.GroupNotFound;
+
+    byte[] updateGroup(
+            byte[] groupId,
+            String name,
+            String description,
+            List<String> addMembers,
+            List<String> removeMembers,
+            List<String> addAdmins,
+            List<String> removeAdmins,
+            boolean resetGroupLink,
+            String groupLinkState,
+            String addMemberPermission,
+            String editDetailsPermission,
+            String avatar,
+            Integer expirationTimer
+            ) throws Error.AttachmentInvalid, Error.Failure, Error.InvalidNumber, Error.GroupNotFound;
+
     String updateGroup(
             String base64GroupId,
             String name,
@@ -124,17 +164,6 @@ public interface Signal extends DBusInterface {
             Integer expirationTimer
             ) throws Error.AttachmentInvalid, Error.Failure, Error.InvalidNumber, Error.GroupNotFound;
 
-    String getGroupName(String base64GroupId);
-
-    // To get the group Ids in base 64 format, either use the getBaseGroupIds() method, or
-    //   the getGroupIds(dummy) form, where dummy represents any string
-    List<String> getBase64GroupIds();
-    List<String> getGroupIds(String dummy);
-
-    void setGroupBlocked(String base64GroupId, boolean blocked) throws Error.GroupNotFound;
-
-    List<String> getGroupMembers(String base64GroupId);
-
     long sendGroupMessage(
             String message, List<String> attachments, String base64GroupId
     ) throws Error.GroupNotFound, Error.Failure, Error.AttachmentInvalid;
@@ -143,10 +172,6 @@ public interface Signal extends DBusInterface {
             String emoji, boolean remove, String targetAuthor, long targetSentTimestamp, String base64GroupId
     ) throws Error.GroupNotFound, Error.Failure, Error.InvalidNumber;
 
-    String updateGroup(
-            String base64GroupId, String name, List<String> members, String avatar
-    ) throws Error.AttachmentInvalid, Error.Failure, Error.InvalidNumber, Error.GroupNotFound;
-
     boolean isRegistered(String number) throws Error.Failure, Error.InvalidNumber;
 
     List<Boolean> isRegistered(List<String> numbers) throws Error.Failure, Error.InvalidNumber;
@@ -201,11 +226,15 @@ public interface Signal extends DBusInterface {
 
     void quitGroup(final byte[] groupId) throws Error.GroupNotFound, Error.Failure;
 
+    void quitGroup(final String base64GroupId) throws Error.GroupNotFound, Error.Failure;
+
     boolean isContactBlocked(final String number) throws Error.InvalidNumber;
 
-    boolean isGroupBlocked(final byte[] groupId);
+    boolean isGroupBlocked(final byte[] groupId)  throws Error.GroupNotFound, Error.Failure;
+    boolean isGroupBlocked(final String base64GroupId)  throws Error.GroupNotFound, Error.Failure;
 
-    boolean isMember(final byte[] groupId);
+    boolean isMember(final byte[] groupId)  throws Error.GroupNotFound, Error.Failure;
+    boolean isMember(final String base64GroupId)  throws Error.GroupNotFound, Error.Failure;
 
     void joinGroup(final String groupLink) throws Error.Failure;
 
diff --git a/src/main/java/org/asamk/signal/dbus/DbusSignalImpl.java b/src/main/java/org/asamk/signal/dbus/DbusSignalImpl.java
index 99bd7ed2..1e68159e 100644
--- a/src/main/java/org/asamk/signal/dbus/DbusSignalImpl.java
+++ b/src/main/java/org/asamk/signal/dbus/DbusSignalImpl.java
@@ -30,6 +30,7 @@ import org.asamk.signal.manager.groups.GroupNotFoundException;
 import org.asamk.signal.manager.groups.GroupPermission;
 import org.asamk.signal.manager.groups.LastGroupAdminException;
 import org.asamk.signal.manager.groups.NotAGroupMemberException;
+import org.asamk.signal.manager.storage.groups.GroupInfo;
 import org.asamk.signal.manager.storage.identities.IdentityInfo;
 import org.asamk.signal.util.DateUtils;
 import org.asamk.signal.util.ErrorUtils;
@@ -226,7 +227,17 @@ public class DbusSignalImpl implements Signal {
             final long targetSentTimestamp, final byte[] groupId
     ) {
         try {
-            final var results = m.sendGroupRemoteDeleteMessage(targetSentTimestamp, GroupId.unknownVersion(groupId));
+            GroupInfo group = null;
+            try {
+                group = m.getGroup(GroupId.unknownVersion(groupId));
+            } catch (AssertionError e) {
+                throw new Error.Failure(e.getMessage());
+            }
+              if (group == null) {
+                throw new Error.GroupNotFound("Error finding group");
+            }
+
+            final var results = m.sendGroupRemoteDeleteMessage(targetSentTimestamp, group.getGroupId());
             checkSendMessageResults(results.first(), results.second());
             return results.first();
         } catch (IOException e) {
@@ -298,7 +309,17 @@ public class DbusSignalImpl implements Signal {
     @Override
     public long sendGroupMessage(final String message, final List<String> attachments, final byte[] groupId) {
         try {
-            var results = m.sendGroupMessage(message, attachments, GroupId.unknownVersion(groupId));
+            GroupInfo group = null;
+            try {
+                group = m.getGroup(GroupId.unknownVersion(groupId));
+            } catch (AssertionError e) {
+                throw new Error.Failure(e.getMessage());
+            }
+              if (group == null) {
+                throw new Error.GroupNotFound("Error finding group");
+            }
+
+            var results = m.sendGroupMessage(message, attachments, group.getGroupId());
             checkSendMessageResults(results.first(), results.second());
             return results.first();
         } catch (IOException e) {
@@ -311,8 +332,12 @@ public class DbusSignalImpl implements Signal {
     }
     @Override
     public long sendGroupMessage(final String message, final List<String> attachments, final String base64GroupId) {
-        byte[] groupId = Base64.getDecoder().decode(base64GroupId);
-        return sendGroupMessage(message, attachments, groupId);
+        try {
+            byte[] groupId = GroupId.fromBase64(base64GroupId).serialize();
+            return sendGroupMessage(message, attachments, groupId);
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure("Invalid group id format: " + e.getMessage());
+        }
     }
 
     @Override
@@ -324,11 +349,21 @@ public class DbusSignalImpl implements Signal {
             final byte[] groupId
     ) {
         try {
+            GroupInfo group = null;
+            try {
+                group = m.getGroup(GroupId.unknownVersion(groupId));
+            } catch (AssertionError e) {
+                throw new Error.Failure(e.getMessage());
+            }
+              if (group == null) {
+                throw new Error.GroupNotFound("Error finding group");
+            }
+
             final var results = m.sendGroupMessageReaction(emoji,
                     remove,
                     targetAuthor,
                     targetSentTimestamp,
-                    GroupId.unknownVersion(groupId));
+                    group.getGroupId());
             checkSendMessageResults(results.first(), results.second());
             return results.first();
         } catch (IOException e) {
@@ -348,8 +383,12 @@ public class DbusSignalImpl implements Signal {
             final long targetSentTimestamp,
             final String base64GroupId
             ) {
-        byte[] groupId = Base64.getDecoder().decode(base64GroupId);
-        return sendGroupMessageReaction(emoji, remove, targetAuthor, targetSentTimestamp, groupId);
+        try {
+            byte[] groupId = GroupId.fromBase64(base64GroupId).serialize();
+            return sendGroupMessageReaction(emoji, remove, targetAuthor, targetSentTimestamp, groupId);
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure("Invalid group id format: " + e.getMessage());
+        }
     }
 
     @Override
@@ -454,6 +493,12 @@ public class DbusSignalImpl implements Signal {
         }
     }
 
+    @Override
+    public void sendTyping(boolean typingAction, byte[] groupId, List<String>recipients) {
+        String base64GroupId = Base64.getEncoder().encodeToString(groupId);
+        sendTyping(typingAction, base64GroupId, recipients);
+    }
+
     // Since contact names might be empty if not defined, also potentially return
     // the profile name
     @Override
@@ -500,8 +545,18 @@ public class DbusSignalImpl implements Signal {
 
     @Override
     public void setGroupBlocked(final byte[] groupId, final boolean blocked) {
+        GroupInfo group = null;
         try {
-            m.setGroupBlocked(GroupId.unknownVersion(groupId), blocked);
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
+        }
+
+        try {
+            m.setGroupBlocked(group.getGroupId(), blocked);
         } catch (GroupNotFoundException e) {
             throw new Error.GroupNotFound(e.getMessage());
         }
@@ -509,8 +564,12 @@ public class DbusSignalImpl implements Signal {
 
     @Override
     public void setGroupBlocked(final String base64GroupId, final boolean blocked) {
-        byte[] groupId = Base64.getDecoder().decode(base64GroupId);
-        setGroupBlocked(groupId, blocked);
+        try {
+            byte[] groupId = GroupId.fromBase64(base64GroupId).serialize();
+            setGroupBlocked(groupId, blocked);
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure("Invalid group id format: " + e.getMessage());
+        }
     }
 
     @Override
@@ -525,9 +584,14 @@ public class DbusSignalImpl implements Signal {
 
     @Override
     public String getGroupName(final byte[] groupId) {
-        var group = m.getGroup(GroupId.unknownVersion(groupId));
-        if (group == null) {
-            return "";
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
         } else {
             return group.getTitle();
         }
@@ -535,9 +599,14 @@ public class DbusSignalImpl implements Signal {
 
     @Override
     public List<String> getGroupMembers(final byte[] groupId) {
-        var group = m.getGroup(GroupId.unknownVersion(groupId));
-        if (group == null) {
-            return List.of();
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
         } else {
             return group.getMembers()
                     .stream()
@@ -571,10 +640,22 @@ public class DbusSignalImpl implements Signal {
 
     @Override
     public String getGroupName(final String base64GroupId) {
-        byte[] groupId = Base64.getDecoder().decode(base64GroupId);
-        var group = m.getGroup(GroupId.unknownVersion(groupId));
-        if (group == null) {
-            return "";
+        byte[] groupId = null;
+        GroupInfo group = null;
+        try {
+            groupId = GroupId.fromBase64(base64GroupId).serialize();
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure(e.getMessage());
+        }
+
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
         } else {
             return group.getTitle();
         }
@@ -582,10 +663,20 @@ public class DbusSignalImpl implements Signal {
 
     @Override
     public List<String> getGroupMembers(final String base64GroupId) {
-        byte[] groupId = Base64.getDecoder().decode(base64GroupId);
-        var group = m.getGroup(GroupId.unknownVersion(groupId));
-        if (group == null) {
-            return List.of();
+        byte[] groupId = null;
+        try {
+            groupId = GroupId.fromBase64(base64GroupId).serialize();
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure("Invalid group id format: " + e.getMessage());
+        }
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
         } else {
             return group.getMembers()
                     .stream()
@@ -615,7 +706,17 @@ public class DbusSignalImpl implements Signal {
                 checkSendMessageResults(0, results.second());
                 return results.first().serialize();
             } else {
-                final var results = m.updateGroup(GroupId.unknownVersion(groupId),
+                GroupInfo group = null;
+                try {
+                    group = m.getGroup(GroupId.unknownVersion(groupId));
+                } catch (AssertionError e) {
+                    throw new Error.Failure(e.getMessage());
+                }
+                  if (group == null) {
+                    throw new Error.GroupNotFound("Error finding group");
+                }
+
+                final var results = m.updateGroup(group.getGroupId(),
                         name,
                         null,
                         members,
@@ -646,14 +747,22 @@ public class DbusSignalImpl implements Signal {
 
     @Override
     public String updateGroup(String base64GroupId, String name, List<String> members, String avatar) {
-        byte[] groupId = Base64.getDecoder().decode(base64GroupId);
+        byte[] groupId = null;
+        if (!base64GroupId.isEmpty()) {
+            try {
+                groupId = GroupId.fromBase64(base64GroupId).serialize();
+            } catch (GroupIdFormatException e) {
+                throw new Error.Failure("Invalid group id format: " + e.getMessage());
+            }
+        }
         groupId = updateGroup(groupId, name, members, avatar);
+
         return Base64.getEncoder().encodeToString(groupId);
     }
 
     @Override
-    public String updateGroup(
-            String base64GroupId,
+    public byte[] updateGroup(
+            byte[] groupId,
             String name,
             String description,
             List<String> addMembers,
@@ -668,13 +777,7 @@ public class DbusSignalImpl implements Signal {
             Integer expirationTimer
             ) {
         try {
-            byte[] groupId = null;
             File avatarFile = null;
-            if (base64GroupId.isEmpty()) {
-                throw new Error.GroupNotFound("No group specified.");
-            } else {
-                groupId = Base64.getDecoder().decode(base64GroupId);
-            }
             if (name.isEmpty()) {
                 name = null;
             }
@@ -711,7 +814,17 @@ public class DbusSignalImpl implements Signal {
                  long fileSize = avatarFile.length();
                  if (fileSize == 0) {
                      try {
-                         AvatarStore.deleteGroupAvatar(GroupId.unknownVersion(groupId));
+                         GroupInfo group = null;
+                         try {
+                             group = m.getGroup(GroupId.unknownVersion(groupId));
+                         } catch (AssertionError ae) {
+                             throw new Error.Failure(ae.getMessage());
+                         }
+                           if (group == null) {
+                            throw new Error.GroupNotFound("Error finding group");
+                        }
+
+                         AvatarStore.deleteGroupAvatar(group.getGroupId());
                      } catch (IOException e) {
                          throw new Error.Failure(e.getMessage());
                      }
@@ -720,9 +833,19 @@ public class DbusSignalImpl implements Signal {
             if (groupId == null) {
                 final var results = m.createGroup(name, addMembers, avatar == null ? null : new File(avatar));
                 checkSendMessageResults(0, results.second());
-                return Base64.getEncoder().encodeToString(results.first().serialize());
+                return results.first().serialize();
             } else {
-                final var results = m.updateGroup(GroupId.unknownVersion(groupId),
+                GroupInfo group = null;
+                try {
+                    group = m.getGroup(GroupId.unknownVersion(groupId));
+                } catch (AssertionError e) {
+                    throw new Error.Failure(e.getMessage());
+                }
+                  if (group == null) {
+                    throw new Error.GroupNotFound("Error finding group");
+                }
+
+                final var results = m.updateGroup(group.getGroupId(),
                         name,
                         description,
                         addMembers,
@@ -739,7 +862,7 @@ public class DbusSignalImpl implements Signal {
                 if (results != null) {
                     checkSendMessageResults(results.first(), results.second());
                 }
-                return base64GroupId;
+                return groupId;
             }
         } catch (UserErrorException | IOException e) {
             throw new Error.Failure(e.getMessage());
@@ -752,6 +875,216 @@ public class DbusSignalImpl implements Signal {
         }
     }
 
+    @Override
+    public String updateGroup(
+            String base64GroupId,
+            String name,
+            String description,
+            List<String> addMembers,
+            List<String> removeMembers,
+            List<String> addAdmins,
+            List<String> removeAdmins,
+            boolean resetGroupLink,
+            String groupLinkState,
+            String addMemberPermission,
+            String editDetailsPermission,
+            String avatar,
+            Integer expirationTimer
+            ) {
+        byte[] groupId = null;
+        if (!base64GroupId.isEmpty()) {
+            try {
+                groupId = GroupId.fromBase64(base64GroupId).serialize();
+            } catch (GroupIdFormatException e) {
+                throw new Error.Failure("Invalid group id format: " + e.getMessage());
+            }
+        }
+        groupId = updateGroup(
+                groupId,
+                name,
+                description,
+                addMembers,
+                removeMembers,
+                addAdmins,
+                removeAdmins,
+                resetGroupLink,
+                groupLinkState,
+                addMemberPermission,
+                editDetailsPermission,
+                avatar,
+                expirationTimer
+                );
+        return Base64.getEncoder().encodeToString(groupId);
+    }
+
+    @Override
+    public String getGroupInviteUri(byte[] groupId) {
+        GroupInfo group = null;
+        GroupInviteLinkUrl groupInviteUri = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
+        }
+        groupInviteUri = group.getGroupInviteLink();
+          if (groupInviteUri == null) {
+              return "";
+        }
+        return groupInviteUri.getUrl();
+    }
+
+    @Override
+    public String getGroupInviteUri(String base64GroupId) {
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.fromBase64(base64GroupId));
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure("Incorrect format: " + e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
+        }
+        GroupInviteLinkUrl groupInviteUri = group.getGroupInviteLink();
+        return groupInviteUri.getUrl();
+    }
+
+    @Override
+    public List<String> getGroupPendingMembers(final byte[] groupId) {
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
+        } else {
+            return group.getPendingMembers()
+                    .stream()
+                    .map(m::resolveSignalServiceAddress)
+                    .map(Util::getLegacyIdentifier)
+                    .collect(Collectors.toList());
+        }
+    }
+
+    @Override
+    public List<String> getGroupPendingMembers(final String base64GroupId) {
+        byte [] groupId = null;
+        try {
+            groupId = GroupId.fromBase64(base64GroupId).serialize();
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure("Incorrect format: " + e.getMessage());
+        }
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
+        } else {
+            return group.getPendingMembers()
+                    .stream()
+                    .map(m::resolveSignalServiceAddress)
+                    .map(Util::getLegacyIdentifier)
+                    .collect(Collectors.toList());
+        }
+    }
+
+    @Override
+    public List<String> getGroupRequestingMembers(final byte[] groupId) {
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
+        } else {
+            return group.getRequestingMembers()
+                    .stream()
+                    .map(m::resolveSignalServiceAddress)
+                    .map(Util::getLegacyIdentifier)
+                    .collect(Collectors.toList());
+        }
+    }
+
+    @Override
+    public List<String> getGroupRequestingMembers(final String base64GroupId) {
+        byte [] groupId = null;
+        try {
+            groupId = GroupId.fromBase64(base64GroupId).serialize();
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure("Incorrect format: " + e.getMessage());
+        }
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
+        } else {
+            return group.getRequestingMembers()
+                    .stream()
+                    .map(m::resolveSignalServiceAddress)
+                    .map(Util::getLegacyIdentifier)
+                    .collect(Collectors.toList());
+        }
+    }
+
+    @Override
+    public List<String> getGroupAdminMembers(final byte[] groupId) {
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
+        } else {
+            return group.getAdminMembers()
+                    .stream()
+                    .map(m::resolveSignalServiceAddress)
+                    .map(Util::getLegacyIdentifier)
+                    .collect(Collectors.toList());
+        }
+    }
+
+    @Override
+    public List<String> getGroupAdminMembers(final String base64GroupId) {
+        byte[] groupId = null;
+        try {
+            groupId = GroupId.fromBase64(base64GroupId).serialize();
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure("base64GroupId" + " is not a valid Base 64 string " + e.getMessage());
+        }
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
+        } else {
+            return group.getAdminMembers()
+                    .stream()
+                    .map(m::resolveSignalServiceAddress)
+                    .map(Util::getLegacyIdentifier)
+                    .collect(Collectors.toList());
+        }
+    }
+
+
+
     @Override
     public boolean isRegistered(String number) {
         if (number.isEmpty()) {
@@ -968,9 +1301,45 @@ public class DbusSignalImpl implements Signal {
 
     @Override
     public void quitGroup(final byte[] groupId) {
-        var group = GroupId.unknownVersion(groupId);
+        GroupInfo group = null;
         try {
-            m.sendQuitGroupMessage(group, Set.of());
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
+        }
+        try {
+            m.sendQuitGroupMessage(group.getGroupId(), Set.of());
+        } catch (GroupNotFoundException | NotAGroupMemberException e) {
+            throw new Error.GroupNotFound(e.getMessage());
+        } catch (IOException | LastGroupAdminException e) {
+            throw new Error.Failure(e.getMessage());
+        } catch (InvalidNumberException e) {
+            throw new Error.InvalidNumber(e.getMessage());
+        }
+    }
+
+    @Override
+    public void quitGroup(final String base64GroupId) {
+        byte [] groupId = null;
+        try {
+            groupId = GroupId.fromBase64(base64GroupId).serialize();
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure("Incorrect format: " + e.getMessage());
+        }
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+          if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
+        }
+        try {
+            m.sendQuitGroupMessage(group.getGroupId(), Set.of());
         } catch (GroupNotFoundException | NotAGroupMemberException e) {
             throw new Error.GroupNotFound(e.getMessage());
         } catch (IOException | LastGroupAdminException e) {
@@ -1008,9 +1377,35 @@ public class DbusSignalImpl implements Signal {
 
     @Override
     public boolean isGroupBlocked(final byte[] groupId) {
-        var group = m.getGroup(GroupId.unknownVersion(groupId));
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
         if (group == null) {
-            return false;
+            throw new Error.GroupNotFound("Error finding group");
+        } else {
+            return group.isBlocked();
+        }
+    }
+
+    @Override
+    public boolean isGroupBlocked(final String base64GroupId) {
+        GroupInfo group = null;
+        byte [] groupId = null;
+        try {
+            groupId = GroupId.fromBase64(base64GroupId).serialize();
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure("Incorrect format: " + e.getMessage());
+        }
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+        if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
         } else {
             return group.isBlocked();
         }
@@ -1018,9 +1413,35 @@ public class DbusSignalImpl implements Signal {
 
     @Override
     public boolean isMember(final byte[] groupId) {
-        var group = m.getGroup(GroupId.unknownVersion(groupId));
+        GroupInfo group = null;
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
         if (group == null) {
-            return false;
+            throw new Error.GroupNotFound("Error finding group");
+        } else {
+            return group.isMember(m.getSelfRecipientId());
+        }
+    }
+
+    @Override
+    public boolean isMember(final String base64GroupId) {
+        GroupInfo group = null;
+        byte[] groupId = null;
+        try {
+            groupId = GroupId.fromBase64(base64GroupId).serialize();
+        } catch (GroupIdFormatException e) {
+            throw new Error.Failure("Incorrect format: " + e.getMessage());
+        }
+        try {
+            group = m.getGroup(GroupId.unknownVersion(groupId));
+        } catch (AssertionError e) {
+            throw new Error.Failure(e.getMessage());
+        }
+        if (group == null) {
+            throw new Error.GroupNotFound("Error finding group");
         } else {
             return group.isMember(m.getSelfRecipientId());
         }