More documentation
diff --git a/doc/compatibility.rst b/doc/compatibility.rst
index cbc0eb3..0cb2ba6 100644
--- a/doc/compatibility.rst
+++ b/doc/compatibility.rst
@@ -42,3 +42,4 @@
    --out=OUTFILENAME  Output filename. Writes to stdout of not specified
    --inform=INFORM    key format of input - default PEM
    --outform=OUTFORM  key format of output - default PEM
+