One reason many have remained on 3.55 CFW is because those users were using the IrisManager as their backup manager.  Now that is not an issue as IrisManager has been updated by D_Skywalk and Estwald to include support for 4.xx custom firmware.

The developer notes and changelog are listed below.

"IrisManager is a port of HermesManager based on PSLIGHT, Tiny3D, PS3Soundlib and OpenPS3FTP, is a completly legal open code manager Made with Homebrew tools.



Changelog:
v1.25 - r84 (commit 63eccf64b7659e2f8e293653c720ac3a159ccac4)

Added Support for 4.30 CFW - thx to Estwald for the help!
IrisManager Now Supports CFW 3.55 and 4.30



UPDATES ON: DO NOT DELETE OLD RELEASE, JUST UPDATE!"

Source