Dear Rémy,

A particular change in BaseX 11.4 that took me a while to find, is a
change in http:send-request. So this is only relevant if you use that
function.
If you send a JSON body, previously you had to serialize it, like:

       http:send-request(
         <http:request method='put'>
           <http:body media-type='application/json'/>
         </http:request>,
         $url,
         serialize($body-map, map{'method':'json'})
       )

This has changed, and the right way to call this is now:

       http:send-request(
         <http:request method='put'>
           <http:body media-type='application/json'/>
         </http:request>,
         $url,
         $body-map
       )

If you use http:send-request, I hope this will save you a bit of time.

Best regards,
Nico Verwer