Just to clarify, here my recent experiences with the update process:
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Keep an eye on VPN / firewall software to not block internet access for the following services.
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You need Google play services activated for the update menu to appear.
com.google.android.gms -
You need Google services framework activated otherwise the update check will not really work.
com.google.android.gsf -
After the update disable both of them if you don’t want them to run by default. Deactivating com.google.android.gms only succeeds if you disable it as a device admin (Even if you disabled it before it registers itself again after the update.)