As you may know, Ubuntu Touch OTA-6 Update is ready, but BQ still has to test it, until it becomes available.
The update for Meizu MX4 and Nexus 4 will be released today, but unfortunately, the BQ users will receive the update next week.
Also worth mentioning, Canonical is working at a power consumption regression and hopes to release it until update gets ready for BQ.
As a reminder, Ubuntu Touch is a stable operating system, but it is not mature enough, compared to Android and iOS. For now, there are three Ubuntu Phones: Bq Aquaris E5 HD, Bq Aquaris E4.5, Meizu MX4, but the system is also officially supported on the LG Nexus 4 device.