# Amazon Neptune Engine Version 1.0.4.2.R5 (2021-08-16)
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As of 2021-08-16, engine version 1.0.4.2.R5 is being generally deployed. Please note that it takes several days for a new release to become available in every region.

## Defects Fixed in This Engine Release
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+ Disabled an optimization made in [engine release `1.0.4.2.R4`](engine-releases-1.0.4.2.R4.md) that made the [Neptune lookup cache](feature-overview-lookup-cache.md) survive engine restarts on replicas. Replica restarts now clear the lookup cache.

## Query-Language Versions Supported in This Release
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Before upgrading a DB cluster to version 1.0.4.2.R5, make sure that your project is compatible with these query-language versions:
+ *Gremlin version:* `3.4.10`
+ *SPARQL version:* `1.1`

## Upgrade Paths to Engine Release 1.0.4.2.R5
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Your cluster will be upgraded to this patch release automatically during your next maintenance window if you are running engine version `1.0.4.2`.

You can manually upgrade any previous Neptune engine release to this release.