In short:
| | Recommendation | |-------------------|--------------------| | You play official UMDs and never go online. | Not necessary. 6.60 works fine. | | You want to sign in to PSN / download purchased games. | Yes. Sony’s modern security requires 6.61. | | You plan to install Custom Firmware (CFW) . | Yes, but note: 6.61 CFW exists, but 6.60 CFW has wider plugin support. Many advanced users stick with 6.60 PRO-C or LME. |
PSP update 6.61 is a firmware update that was released by Sony in 2011. This update improved the overall stability of the system and fixed some bugs.