We have just released version 0.4.4 of the Dimensions VIP client. This version includes an improved messaging app as the only functional update but more importantly, it contains the start of a major architectural update that will improve performance by many factors.
Due to major internal changes in this version, we highly encourage anyone experience problems to reach out to us via the in-game feedback system or here through the Steam community forums. We are monitoring carefully and have tested extensively but there's always the slight chance that we're not perfect.