Oracle/PeopleSoft made Elasticsearch our new search engine as of PeopleTools 8.55.11, which was released in November 2016. At that time, we announced that Oracle's Secure Enterprise Search would no longer be supported as of April 2018. That date is rapidly approaching.
Oracle recommends that customers move to Elasticsearch as soon as possible. Do not deploy new instances of Oracle Secure Enterprise Search (SES) as the search engine with the PeopleSoft Search Framework. Elasticsearch is the only search engine supported in PeopleTools 8.56. In fact, SES will reach end of life as of January 31, 2018. At that date, no new patches, certifications, or security vulnerability (SV) fixes will be available. As of April 30, 2018, support for SES as the search engine for PeopleSoft Search Framework will also no longer include new patches or fixes. After April 30, 2018, Oracle will continue to provide sustaining support for SES as the search engine for PeopleSoft Search Framework on a best-effort basis, but the support will not include any patches or new fixes. In addition, support for Verity also ends on April 30th 2018.
For more information on deploying Elasticsearch with PeopleSoft, see the Search Concepts page on peoplesoftinfo.com. That page contains useful information and links to other valuable content like the Elasticsearch page on My Oracle Support. There is also information on transitioning to Elasticsearch from SES.