Let Go and UMS is in the vein of Alternative Rock. Though they were classified in a whole lot more genres but it was considered Alt Rock. And the songs are in the vein of that genre. I think Avril's next album may be the same considering Let Go is a heavy-guitar laden album while UMS is a heavy-piano laden album and Avril said that the next album would have a lot of guitars and pianos but it's upbeat. Unlike other's idea on 5th album that it will be like GL upbeat 2.0, my idea is that its an LG + UMS type of album.