A5c-2 How can I tell

How do I know if I have an A5c or an A5c-2?
I have recently bought 3 A5c’s and I’m thinking they are A5c-2 becuae they don’t work right with 2.5.4

Hi @George2,

I don’t believe you can put 2.5.4 on the A5c2. Can you send me serial numbers of the 3 units and I’ll see when they were made?