--- a/src/Doc/Implementation/ML.thy Fri Mar 02 11:52:27 2018 +0100
+++ b/src/Doc/Implementation/ML.thy Fri Mar 02 15:16:10 2018 +0100
@@ -23,7 +23,7 @@
explanations should help to understand how proper Isabelle/ML is to be read
and written, and to get access to the wealth of experience that is expressed
in the source text and its history of changes.\<^footnote>\<open>See
- \<^url>\<open>http://isabelle.in.tum.de/repos/isabelle\<close> for the full Mercurial history.
+ \<^url>\<open>https://isabelle.in.tum.de/repos/isabelle\<close> for the full Mercurial history.
There are symbolic tags to refer to official Isabelle releases, as opposed
to arbitrary \<^emph>\<open>tip\<close> versions that merely reflect snapshots that are never
really up-to-date.\<close>