diff --git a/NEWS b/NEWS
index 6bdebd23..33b58f38 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,9 @@
 Noteworthy changes in version 1.21.0 (unreleased)
 -------------------------------------------------
 
+ * Error::isCanceled now also returns true for error code
+   GPG_ERR_FULLY_CANCELED.  [T6510]
+
 
 Noteworthy changes in version 1.20.0 (2023-04-20)
 -------------------------------------------------
diff --git a/doc/gpgme.texi b/doc/gpgme.texi
index 606d13bb..bc89792a 100644
--- a/doc/gpgme.texi
+++ b/doc/gpgme.texi
@@ -1649,6 +1649,11 @@ when requested.
 @item GPG_ERR_CANCELED
 This value means that the operation was canceled.
 
+@item GPG_ERR_FULLY_CANCELED
+This value means that the operation was canceled. It is sometimes returned
+instead of @code{GPG_ERR_CANCELED} for internal reasons in GnuPG. You should
+treat both values identically.
+
 @item GPG_ERR_INV_ENGINE
 This value means that the engine that implements the desired protocol
 is currently not available.  This can either be because the sources
diff --git a/lang/cpp/src/context.cpp b/lang/cpp/src/context.cpp
index 7667eb30..bdcfabed 100644
--- a/lang/cpp/src/context.cpp
+++ b/lang/cpp/src/context.cpp
@@ -142,7 +142,7 @@ int Error::sourceID() const
 
 bool Error::isCanceled() const
 {
-    return code() == GPG_ERR_CANCELED;
+    return code() == GPG_ERR_CANCELED || code() == GPG_ERR_FULLY_CANCELED;
 }
 
 int Error::toErrno() const