I adjusted vardiff settings to consider longer time period. This should result in difficulty not jumping as low and high as previously.
I wasn't going to launch the new stratum server until the weekend but issues with servers this morning pushed me to do this. I was going to make a proper announcement, but yes:
The new stratum server has vardiff working again. It's also much more efficient so it should result in much lower rejects ratio when mining fast coins (we already had low rejects when mining big coins, but our rejects when mining low difficulty coins were a bit higher than should be). This is a very optimised software and it should give us all great results.
All your feedback about how it works is appreciated.