A new PSP Firmware Update is now available via Network Update and linked below. Thus far, only one familiar change is listed in the changelog:

Not an exciting update, although it means more PSN titles for PSP are forthcoming which will likely require Firmware 3.73. Additionally, Service Mode has been confirmed as working and PSAR Dumper decrypts everything for those wondering.

Download Official 3.73 Firmware here

** This will make you lose ALL homebrew compatibility.