queue simple set [find max-limit=10M/10M] max-limit=15M/15M
This command is not working in this version. Is it bug or just command is changed.
I have had trouble with that with earlier versions as well. My workaround has always been to use another match to select the queue items to change.
(never persisted to find what is really going wrong there, but selecting on a match with the current limit values never seems to work)
New version 6.48.2 has been released in stable RouterOS channel:
http://forum.mikrotik.com/t/v6-48-2-stable-is-released/148381/1