If you are one of the masses who doesn't want to update your system you can bypass the mandatory PS3 update by using Yet Another Bypass by cotojestwtf.A  To be clear this IS NOT for cfw users and won't give access to SEN on any CFW.A  What it does is give OFW users who are on OFW 4.0 the ability to bypass the mandatory update and utilize SEN.

Version 1.6: Bypass 4.11 on 4.00

Supported Regions:AU, EU, JP, UK, US.

How to:

• Start bat file YABStart
• Set up on PS3/Proxy Seetings IP: of your computer.
• Set up on PS3/Proxy Seetings Port: 27 u can change them on config folder (port.txt).
• Connect to PSN
• Succesfully bypassed 4.11 on 4.00

Source:A  http://www.ps3hax.net/showthread.php?p=330763