I have Samsung j5, now just with 1GB free space memory, and system recomanded to upgrade to Android Marsh. 6.1.1 that required 900MB. Sometimes I canceled this update but It cant stop, everyday make me request to aproved update.
I asked you, if I upgrade system 6.0.1 then will delete something, can it earn more space with that or not!!?
Regrads!
What others do after an update is factory reset cause usually it takes more space.