Upgraded my old 2008 MacBook unibody (MacBook5,1) to Mojave with no problems! Only issue I've seen so far is the known issue about sidebar shading, which isn't noticeable when all's kept in Dark Mode
One question for anyone listening: I kept my internal third-party SSD formatted HFS+ extended journaled, but am curious – is there any performance improvement if I format the drive for APFS? Has anyone tested performance or run benchmarks on third-party SSDs in Mojave that use HFS+ vs. APFS?
(Several articles written last year during High Sierra said APFS performance slightly lagged HFS+, but wonder if that's improved now under Mojave.) Thanks!