DSM 7 and Plex update sort of successful

[SuperDragonite]

DSM 7 - Plex Media Server - Release Info & Migration instructions

Plex Media Server for Synology DSM 7 - Release This document is to share changes made with DSM 7 and resolve any unforeseen issues before you attempt migrating to DSM 7 for Plex use YOU ARE URGED TO READ THIS THREAD COMPLETELY BEFORE PROCEEDING OR ASKING QUESTIONS DO NOT INSTALL Synology BETA software UNLESS INSTRUCTED. This thread is a LIVING document. Expect it to change. Synology’s DiskStation Manager (DSM) has undergone significant changes in version 7.0. Many of those changes affected …

According to this post, you are good to delete the Plex folder after successful migration. PlexMediaServer is the new database/application folder.