We have a dozen odd pix 515e, 525 and 535's in our organization with v6.1 software.
Per cisco these models are EOL/EOS.
Also the latest Pix Software for these appear to be EOL as well
My question is can the software on these pix boxes be upgraded ?or are the softwares for the PIX boxes EOL/EOS as well ?
In which case migrating over to ASA's the only option ?
Also is there a number or person we can reach out in Cisco to get some suggestions ??
There was an upgrade kit for version 7.X for those models which allowed you to increase the RAM on those models and then upgrade to version 7.x.
In my personal opinion it would be a good idea to start thinking on migrating to ASAs since support for the PIX models will end soon.
You could contact a Local Cisco Parter so that they can help you with the right ASA models and with the price of it.
Don't bother upgrading those devices. You are better off rewriting the policies for new ASAs and cleaning up the configs while you are at it.
6.x is very old now. I hope you don't have conduit statements but if you do there is a tool to convert them to access-lists at least.