CFW rogero question

I have a old fat ps3 60gb version backwards compatible, fw on 3.7.. can i upgrade to the new 4.2.1 rogero cfw? i heard that if u have the old model not the 3k version or whatever that u can upgrade but than i also read that u have to be on cfw 3.55?? can anyone confirm this before i even try to attempt anything
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NVM, please delete this thread, i found the answer
sorry mods