The Staatsarchiv Berne changed their web-link from http to https (finally) so I have to change my weblinks in the sources from:
The number is changing so only the part before = has to be changed.
A change in the citations is done, but in the sources I found no way
RM Search & Replace is very restricted. Within RM, the best you can do is Find Everywhere and click on each instance to edit it, one at a time.
Otherwise, bulk correction has to be done outside RM, either by SQLite ops on the RM database or by exporting the data to a tool that can do it. The latter risks collateral losses.
Perhaps setting your browser to prefer https links would also work.