This news comes from Scott Hartsman, who posted a lengthy preview of RIFT's beta 5 event on the official forums today. Announcing that beta 5 will be "twice as big" as the previous beta event, Hartsman revealed that the team is increasing the number of servers from 18 to 32, which should allow for up to double the amount of players.
Other changes in store for players this week include a better organization of planar currencies, Rogue energy fixes, ranged sound improvements and "significant love" for invasion mechanics. Hartsman also revealed a few items that the team is working on for future updates, such as better racial abilities and master looting. You can read his full announcement here.