I did that by automatically updating to nightlies. I wasn't planning to update yet so I didn't read anything about it. It took me a few hours to realize that I had to manually install gapps again. Now I'm planning a wipe and reinstall as some things don't work (like Keep and Drive sync).
If you're not plannning to beta test CM10.2 and provide feedback to the developers, I would advise you to stick to 10.1.2 for another while.
Have a nice day!
Nokia 5110 > Alcatel OT303 > Nokia 3310 > Nokia 1100 > Nokia 1112 > Nokia 5000 > Nokia 6555 > Nokia 3120C > Nokia E51 > Nokia E52 > Motorola Defy > Galaxy Nexus
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