====== S3 Retention (Object Version Level) ======

**What it is:** Retention is applied to an **object version**, controlling deletion/overwrite until a certain time.

**What it’s for:**
  * Enforce “keep data until date X” per version (compliance).

**Two valid exam facts:**
  * **Different versions of the same object can have different retention modes and periods.**
  * **If you apply retention explicitly to an object version, you specify a Retain Until Date for that object version.**

**Key idea: Retain Until Date**
  * A timestamp/date after which the object version can be modified/deleted (depending on permissions and mode).

**Hard words:**
  * *object version* /ˈɑːbdʒekt ˈvɝːʒn/: phiên bản object
  * *mode* /moʊd/: chế độ
  * *timestamp* /ˈtaɪmstæmp/: mốc thời gian