If the fix is applicable to the next branch then you should submit your fix on the next branch following the DevPolicy instructions. It may be backported to the -stable branches at the next update.
There are V2.8-stable and V3-stable branches too, but we typically don't send patches for them. Is the fix really only applicable to 2.8.3? If so, is it because it's already fixed on the next branch?
If you get your fix submitted soon there's a decent chance it could be include in the 2.8.4 and 3.3 updates.
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Kaleb