Requirements taken straight from the California Vehicle Code:
(1) A vehicle that meets the state’s super ultra-low emission vehicle (SULEV) standard for exhaust emissions and the federal inherently low-emission vehicle (ILEV) evaporative emission standard, as defined in Part 88 (commencing with Section 88.101-94) of Title 40 of the Code of Federal Regulations.
(2) A vehicle that was produced during the 2004 model year or earlier and meets the state’s ultra-low emission vehicle (ULEV) standard for exhaust emissions and the federal ILEV standard. A decal, label, or other identifier issued pursuant to this paragraph is valid until January 1, 2019.
(3) A vehicle that meets the state’s enhanced advanced technology partial zero-emission vehicle (enhanced AT PZEV) standard or transitional zero-emission vehicle (TZEV) standard.
(4) A decal, label, or other identifier issued pursuant to paragraph (1) or (3) before January 1, 2017, is valid until January 1, 2019.
(5) (A) A decal, label, or other identifier issued pursuant to paragraph (1) or (3) on or after January 1, 2017, and before March 1, 2018, is valid until January 1, 2019.
(B) A decal, label, or other identifier issued pursuant to paragraph (1) or (3) between March 1, 2018, and January 1, 2019, is valid until January 1, 2022.
(C) A decal, label, or other identifier issued pursuant to paragraph (1) or (3) on or after March 1, 2018, for a vehicle that had been issued a decal, label, or other identifier pursuant to paragraph (1) or (3) between January 1, 2017, and March 1, 2018, is valid until January 1, 2022.
Zero Emission Vehicles (ZEV) fall into category 1 and therefore qualify for a HOV sticker. Expiration is based on when your sticker was issued, see paragraph B above. Stickers issued on or after March 1, 2018 are good till 2022. Only red stickers have been issued since March, so red is dead in 2022. Nothing left to speculate about.