public void setEngineVersion(String engineVersion) {
        this.engineVersion = engineVersion;
    }
<p>
The upgraded version of the cache engine to be run on the cache nodes.
</p>
<p>
<b>Important:</b> You can upgrade to a newer engine version (see <a
href="https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/SelectEngine.html#VersionManagement">Selecting
a Cache Engine and Version</a>), but you cannot downgrade to an earlier engine version. If you want to use an
earlier engine version, you must delete the existing cluster and create it anew with the earlier engine version.
</p>

@param engineVersion
       The upgraded version of the cache engine to be run on the cache nodes.</p>
       <p>
       <b>Important:</b> You can upgrade to a newer engine version (see <a
       href="https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/SelectEngine.html#VersionManagement"
       >Selecting a Cache Engine and Version</a>), but you cannot downgrade to an earlier engine version. If you
       want to use an earlier engine version, you must delete the existing cluster and create it anew with the
       earlier engine version.
aws-java-sdk-elasticache/src/main/java/com/amazonaws/services/elasticache/model/ModifyCacheClusterRequest.java