With the release of Ektron 8.6, we have made significant changes to the Search Server configuration, requiring an upgrade to the search components that make your search environment incompatible with an Ektron 8.5 install.
If you upgrade an Ektron site to version 8.6, you must also upgrade Ektron search components to 8.6. Version 8.5 search components are incompatible with 8.6 Ektron sites. An 8.5 site cannot share a Search Serverinstance with an 8.6 site. Once the Ektron CMS (site and database) is upgraded to 86, search component should also be upgraded to 8.6 by running "EktronSearchConfiguration.exe" on the Search Server. This executable is located in the 8.6 base installdirectory, for example: C:\Program Files (x86)\Ektron\CMS400v86\Utilities\SearchServer. Running this executable will upgrade the search components from 8.5 to 8.6.