Exchange 2010 - Exchange 2010 cross forest migration

I am working on a clients cross forest migration. Each have Exchange 2010 however i just found out the one forest is on SP2 and the other fully up to date. Does anyone know if this would stop the mailbox moves? I plan to test but wanted to see if any of you had come across this first. Thank you in advance.
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exchange 2010 SP3 with RU 11/ 12 would be required only if you planned to transition it to exchange 2013 or above

Your scenario is cross forest migration, for that what you have is sufficient, no need to update anything
Check below link for major steps

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