Although 3.x may be depreciated, there are many GL iNet users who continue to rely on it, as GL iNet reneged on their commitments to provide 4.x firmware for several models that were still under support long after 4.x was released.
Notably, GL iNet was selling new USB150 routers on their Amazon store as recently as May 2024. According to GL iNet's policy, all newly purchased routers from Amazon are covered by a 2-year warranty. Therefore, these USB150 routers should receive 3.x security updates until at least May 2026, provided GL iNet adheres to their stated policies.