Vine isn't a platform known for outstanding videography, on account of being limited to mobile cameras (not to mention the time limit). But starting today, users on Android should notice a definite improvement in the quality of uploaded videos, at least according to the latest app update. Of course, the quality will still be limited by your phone or tablet's camera and the shooting conditions in any particular location. Exactly how video quality is being improved (bitrate bump? Resolution? Post-processing?) hasn't been addressed.
The only other notable update is to the notification options. I'm not a regular Vine user myself, but the Settings menu now includes options to display Likes, Comments, Re-vines, Mentions, and Follows in either a semi-curated "tailored to you" fashion or from anyone. You can also turn them off. On/off toggles for VMs, new contacts, and milestones of loops, likes, and followers are also included.
Several recent reviews note that the latest update has created performance and crashing issues, particularly on Samsung devices.