diff --git a/src/libsync/accessmanager.cpp b/src/libsync/accessmanager.cpp
index 26f392698..8cba1a71d 100644
--- a/src/libsync/accessmanager.cpp
+++ b/src/libsync/accessmanager.cpp
@@ -95,8 +95,15 @@ QNetworkReply *AccessManager::createRequest(QNetworkAccessManager::Operation op,
 
 #if QT_VERSION >= QT_VERSION_CHECK(5, 9, 4)
     // only enable HTTP2 with Qt 5.9.4 because old Qt have too many bugs (e.g. QTBUG-64359 is fixed in >= Qt 5.9.4)
+
+    /* Disable http2 for now due to Qt bug but allow enabling it via env var, see: https://github.com/owncloud/client/pull/7620
+     *   and: https://github.com/nextcloud/desktop/pull/1806
+     * Issue: https://github.com/nextcloud/desktop/issues/1503
+     */
     if (newRequest.url().scheme() == "https") { // Not for "http": QTBUG-61397
-        newRequest.setAttribute(QNetworkRequest::HTTP2AllowedAttribute, true);
+        static const bool http2EnabledEnv = qEnvironmentVariableIntValue("OWNCLOUD_HTTP2_ENABLED") == 1;
+
+        newRequest.setAttribute(QNetworkRequest::HTTP2AllowedAttribute, http2EnabledEnv);
     }
 #endif