The Ajax requests worked before the upgrades.
It is just a simple ajax call to upload a jpg file to a photo album of my family.
Everything else works - updates to text records etc.
I am using the exact same code on another free hosting site (Byethost) and everything there works perfectly.
I've only noticed this after the upgrades.
Tried the usual bypass for mod_security2 settings, but I think I read somewhere that no bypass is allowed on this site.
Thanks for your help - I would really like to fix this issue. The other site is a bit slow.