What does MR version stand for?

Question

Today I got Android ICS update. The system shows version "Ice Cream Sandwich MR1". I know alpha, beta, rc, rtm, etc. but I was wandering what MR stands for.

Answer 1

I think it means Maintenance Release 1.

Source: I just heard it somewhere on a different application using MR in their version.

Answer 2

mr = "maintenance release", fr = "factory rom".

JBQ

(via "Kernel suffixes," Android Building mailing list)

JBQ is a former tech lead of the Android Open Source Project.

Answer 3

It could also mean Manufacturer's Release. As in this is the release your Manufacturer did, in this case Google. Motorola would have a completely different MR1 release in this case.

Answer 4

MR is maintenance release while SMR is Security maintenance release. To keep the phone secure and bug free, ODMs generally provide updates.