Plex withdrew 1.32.6 and 1.32.7 due to transcoding problems.
If you wish to install an older version on Synology, uninstall the current version first. Synology does not support direct downgrades.
DSM 6: Uninstall then install the desired version of PMS.
DSM 7: When uninstalling, choose the “Uninstall Only” option. Then install the desired version.
Additional Info: