diff --git a/dev/Model/FolderCollection.js b/dev/Model/FolderCollection.js
index dc3a0f928..73681b096 100644
--- a/dev/Model/FolderCollection.js
+++ b/dev/Model/FolderCollection.js
@@ -236,9 +236,11 @@ export class FolderModel extends AbstractModel {
 		if (folder) {
 			folder.deep = json.FullNameRaw.split(folder.delimiter).length - 1;
 
-			let type = folder.metadata[FolderMetadataKeys.KolabFolderType]
-				|| folder.metadata[FolderMetadataKeys.KolabFolderTypeShared];
-			type && !type.includes('mail.') && folder.kolabType(type);
+			let type = (folder.metadata[FolderMetadataKeys.KolabFolderType]
+				|| folder.metadata[FolderMetadataKeys.KolabFolderTypeShared]
+				|| ''
+			).split('.')[0];
+			type && 'mail' != type && folder.kolabType(type);
 
 			folder.messageCountAll = ko.computed({
 					read: folder.privateMessageCountAll,
diff --git a/dev/Settings/User/Folders.js b/dev/Settings/User/Folders.js
index 7a4c1b4f2..cf48eb545 100644
--- a/dev/Settings/User/Folders.js
+++ b/dev/Settings/User/Folders.js
@@ -139,6 +139,7 @@ export class FoldersUserSettings /*extends AbstractViewSettings*/ {
 
 	toggleFolderKolabType(folder, event) {
 		let type = event.target.value;
+		// TODO: append '.default' ?
 		Remote.folderSetMetadata(()=>0, folder.fullNameRaw, FolderMetadataKeys.KolabFolderType, type);
 		folder.kolabType(type);
 	}
diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/FolderInformation.php b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/FolderInformation.php
index d2d87fb41..e081c7169 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/FolderInformation.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/FolderInformation.php
@@ -38,11 +38,13 @@ class FolderInformation
 	public $PermanentFlags = array();
 
 	/**
+	 * https://datatracker.ietf.org/doc/html/rfc3501#section-7.3.1
 	 * @var int
 	 */
 	public $Exists = null;
 
 	/**
+	 * https://datatracker.ietf.org/doc/html/rfc3501#section-7.3.2
 	 * @var int
 	 */
 	public $Recent = null;
diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ResponseCollection.php b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ResponseCollection.php
index 932433203..20b85354f 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ResponseCollection.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ResponseCollection.php
@@ -320,27 +320,33 @@ class ResponseCollection extends \MailSo\Base\Collection
 					$oResult->Flags = $oResponse->ResponseList[2];
 				}
 
-				if (is_array($oResponse->OptionalResponse) && \count($oResponse->OptionalResponse) > 1) {
-					if ('PERMANENTFLAGS' === $oResponse->OptionalResponse[0]
-					 && is_array($oResponse->OptionalResponse[1]))
-					{
-						$oResult->PermanentFlags = $oResponse->OptionalResponse[1];
-					}
-					else if ('UIDVALIDITY' === $oResponse->OptionalResponse[0])
-					{
-						$oResult->Uidvalidity = (int) $oResponse->OptionalResponse[1];
-					}
-					else if ('UNSEEN' === $oResponse->OptionalResponse[0])
-					{
-						$oResult->Unread = (int) $oResponse->OptionalResponse[1];
-					}
-					else if ('UIDNEXT' === $oResponse->OptionalResponse[0])
-					{
-						$oResult->Uidnext = (int) $oResponse->OptionalResponse[1];
-					}
-					else if ('HIGHESTMODSEQ' === $oResponse->OptionalResponse[0])
-					{
-						$oResult->HighestModSeq = (int) $oResponse->OptionalResponse[1];
+				if (\is_array($oResponse->OptionalResponse)) {
+					if (\count($oResponse->OptionalResponse) > 1) {
+						if ('PERMANENTFLAGS' === $oResponse->OptionalResponse[0]
+						 && is_array($oResponse->OptionalResponse[1]))
+						{
+							$oResult->PermanentFlags = $oResponse->OptionalResponse[1];
+						}
+						else if ('UIDVALIDITY' === $oResponse->OptionalResponse[0])
+						{
+							$oResult->Uidvalidity = (int) $oResponse->OptionalResponse[1];
+						}
+						else if ('UNSEEN' === $oResponse->OptionalResponse[0])
+						{
+							$oResult->Unread = (int) $oResponse->OptionalResponse[1];
+						}
+						else if ('UIDNEXT' === $oResponse->OptionalResponse[0])
+						{
+							$oResult->Uidnext = (int) $oResponse->OptionalResponse[1];
+						}
+						else if ('HIGHESTMODSEQ' === $oResponse->OptionalResponse[0])
+						{
+							$oResult->HighestModSeq = (int) $oResponse->OptionalResponse[1];
+						}
+					} else if ('READ-ONLY' === $oResponse->OptionalResponse[0]) {
+//						$oResult->IsWritable = false;
+					} else if ('READ-WRITE' === $oResponse->OptionalResponse[0]) {
+//						$oResult->IsWritable = true;
 					}
 				}