Rarely. You can expect 2–3 updates per year in the first 2 years after purchase, then security patches only.
Some of the key features of the TCL 50EP660's firmware include: Firmware TCL 50EP660
As one user on the XDA Forums noted, a simple firmware update from version V645 to a newer build resolved a persistent issue where the TCL 50EP660 would randomly turn off while watching YouTube. This real-world example highlights how critical keeping your firmware current is for a stable user experience. Rarely