I think it actually depends on the NAS model. If you have a 32-bit processor you cannot run a 64-build of PHP.
Some of Synology's lower end NAS have 32-bit ARM processors. Some older lowerβend NAS have old Celeron processors which only support 32-bit code. I suspect this is the case with your NAS.
For what it's worth, the Synology DS218+ we have at the office has a 64-bit build of PHP. Its processor is an Intel Celeron J3355 which does support 64-bit code, and DSM on this NAS is indeed 64-bit.
I honestly could not find anything with a 32-bit processor, or at least able to run a 32-bit OS, to test Akeeba Backup 9.6.0 with. That's why there was no 32-bit support; it was something I could not test. The fix I made was basically me working blind, just based on the scant information of the error message you got. I am glad I could get it right the first time :)
Nicholas K. Dionysopoulos
Lead Developer and Director
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