diff --git a/doc/man/cryfs.1 b/doc/man/cryfs.1
index 9b57ed35..7e7ea0dd 100644
--- a/doc/man/cryfs.1
+++ b/doc/man/cryfs.1
@@ -157,6 +157,12 @@ Run CryFS in the foreground. Stop using CTRL-C.
 .
 .
 .TP
+\fB\-\-allow-filesystem-upgrade\fI
+.
+Allow upgrading the file system if it was created with an old CryFS version. After the upgrade, older CryFS versions might not be able to use the file system anymore.
+.
+.
+.TP
 \fB\-\-logfile\fR \fIfile\fR
 .
 Write status information to \fIfile\fR. If no logfile is given, CryFS will