Steam recently changed the default privacy settings for all users. This may impact tracking. Ensure your profile has the correct settings by following the guide on our forums.
I was wondering the same thing the other day. I have 3.90 m33-3 and i have had the hardest time getting all the emulators to work on my psp and now that I have finally got them, Im afraid that if I upgrade I will have problem running some of the emus.
Actually take surfer's advice. Cause 3.80/3.90M33 had a memory stick issue and seems to be resolved in 4.01M33.
The memory stick patch was a pain in the ass.