Months! Although this after-the-fact approval notice isn't required for reentry. The I-129S is associated with a blanket L application so this would only be r

Months! Although this after-the-fact approval notice isn't required for reentry. The I-129S is associated with a blanket L application so this would only be relevant if you obtained a blanket L and if you did, you definitely should be keeping in your passport and presenting to CBP an endorsed copy.