Of course, if you use your NAS just for Sooloos
Sadly I see no 'Sooloos only' option - It kind of needs things like 'the NAS' working
i.e. Rebuild of RAID, addition / swapping / replacement of drives, new drive compatibility, remote administration, etc...
Running into problems fixed by later versions isn't going to get much sympathy/support from QNAP
As I posted recently, I am unclear whether a simple change of file name would allow that firmware to be used with other QNAP x86 NASes.
Since the QNAP updates include the kernel, installing an antique version of the kernel that does not include drivers to talk to the disk / network / hardware platform, that may not be 'good?'
Any protection in the updates to prevent ending up with a brick, may not help if you've tampered with the update.
Matt.