Well, you have been asking how to identify the revision of the WiiM Amp prior to buying it. The answer is: There is no 100% safe way to know without either connecting it to the network and accessing the HTTP API or opening the actual case.
If the seller didn't do one thing or the other he cannot know the "PCB_version" for sure, no matter what he says. So far, we know of PCB_version 2, 4 and 5. So, what does "this is the second version" really mean?
There are certain hints toward the newer versus the older versions:
- Red RCA socket must be on the left side (watched from behind)
- The box should have the black and white icons
- There should be the IEC class II mark on the bottom of the unit
View attachment 5732
- Current production samples made in 2024 have a serial number starting with P1TF24
It has been guessed that this unit most probably was a PCB_version 4. It might work just fine, but if it is, it's simply not the latest revision. Why would you want to buy this particular unit from this particular seller, if not because of a discounted price?