diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ImapClient.php b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ImapClient.php
index 593a6ca27..14c046b58 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ImapClient.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ImapClient.php
@@ -1321,4 +1321,9 @@ class ImapClient extends \MailSo\Net\NetClient
 		return $this->UTF8 ? $sText : \MailSo\Base\Utils::Utf7ModifiedToUtf8($sText);
 	}
 
+	public function isUTF8() : bool
+	{
+		return $this->UTF8;
+	}
+
 }
diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/Requests/SORT.php b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/Requests/SORT.php
index 3f239b045..9663a2a97 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/Requests/SORT.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/Requests/SORT.php
@@ -99,7 +99,8 @@ class SORT extends Request
 		$sSearchCriterias = (\strlen($this->sCriterias) && '*' !== $this->sCriterias) ? $this->sCriterias : 'ALL';
 
 		if (!$this->sCharset) {
-			$this->sCharset = \MailSo\Base\Utils::IsAscii($sSearchCriterias) ? 'US-ASCII' : 'UTF-8';
+			$this->sCharset = (!$this->oImapClient->isUTF8() && \MailSo\Base\Utils::IsAscii($sSearchCriterias))
+				? 'US-ASCII' : 'UTF-8';
 		}
 
 		$aRequest[] = \strtoupper($this->sCharset);
diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/Requests/THREAD.php b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/Requests/THREAD.php
index 23ab52b49..e35d44992 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/Requests/THREAD.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/Requests/THREAD.php
@@ -57,7 +57,8 @@ class THREAD extends Request
 		$sSearchCriterias = (\strlen($this->sCriterias) && '*' !== $this->sCriterias) ? $this->sCriterias : 'ALL';
 
 		if (!$this->sCharset) {
-			$this->sCharset = \MailSo\Base\Utils::IsAscii($sSearchCriterias) ? 'US-ASCII' : 'UTF-8';
+			$this->sCharset = (!$this->oImapClient->isUTF8() && \MailSo\Base\Utils::IsAscii($sSearchCriterias))
+				? 'US-ASCII' : 'UTF-8';
 		}
 
 		$aRequest[] = \strtoupper($this->sCharset);