Always sort lists of API versions for easier comparison.

bramble-api/src/main/java/org/briarproject/bramble/api/mailbox/MailboxProperties.java

@@ -85,7 +85,8 @@ public class MailboxProperties {
 					onion.equals(m.onion) &&
 					authToken.equals(m.authToken) &&
 					NullSafety.equals(inboxId, m.inboxId) &&
-					NullSafety.equals(outboxId, m.outboxId);
+					NullSafety.equals(outboxId, m.outboxId) &&
+					serverSupports.equals(m.serverSupports);
 		}
 		return false;
 	}

bramble-api/src/main/java/org/briarproject/bramble/api/mailbox/MailboxStatus.java

@@ -67,6 +67,13 @@ public class MailboxStatus {
 		return attemptsSinceSuccess;
 	}
 
+	/**
+	 * Returns the mailbox's supported API versions.
+	 */
+	public List<MailboxVersion> getServerSupports() {
+		return serverSupports;
+	}
+
 	/**
 	 * @return true if this status indicates a problem with the mailbox.
 	 */