If you face any issues after updating the WP Mobile Menu, in first place check if you have any cache plugin and purge it’s cache.
The cache plugins can be showing some of the old files and that can cause problems, there is no workaround to avoid that since that’s what cache plugins do. Just purging the cache can be enough to sort it.
It it’s not a cache issue then it can be some kind of error in the new version that wasn’t catched in the testing phase.
Contact immediatly our support at firstname.lastname@example.org and explain the situation so we can help as fast as possible.
Remember you can always revert to the previous version if it’s something urgent to sort.