# Review compatibility changes and depreciated features

+ Review compatibility changes and depreciated features in the release note of a specific TiDB version
  +  If any changes affect your upgrade, take actions accordingly.
  +  E.g. TiDB 7.5.0 Compatibility Changes (https://docs.pingcap.com/tidb/stable/release-7.5.0#compatibility-changes)
  +  E.g. TiDB 6.5.0 Compatibility Changes (https://docs.pingcap.com/tidb/v6.5/release-6.5.0#compatibility-changes)

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For example, in TiDB 7.5.0, compatibility changes includes:
+ **`tidb_enable_fast_analyze`** is deprecated.
+ The default value for **`tidb_analyze_partition_concurrency`** is changed from 1 to 2.
+ etc.

For example, in TiDB 6.5.0, compatibility changes includes:
+ **`disconnect-on-expired-password`** is added.
+ The default value for **`cdc.min-ts-interval`** is changed from 1s to 200 ms.
+ etc.