is a Premiere the same as a Series 4?

Like many others, I got a letter from Xfinity regarding MPEG-4 being required, I'm trying to determine if I will need to replace my Tivo.

When I display System Information, it displays that it is a "Series 4"...
It looks like a Premiere, but it's been a few years since I bought it...
I would just check the model, but I'd have to do some disassembly of my "Entertainment Center" to get a look at the back.

Update: Model number is TCD746320 ...

Thanks in advance for any help,

Pat