ANSI/ASHRAE Standard 135-2020 (BACnet) was published in October 2020 as Protocol Revision 22. This update to the 135 standard includes the 21 addenda to 135-2016 and the 93 errata found in 135-2016.
With the latest published addenda to Standard 135-2020, the Standard 135 Protocol Revision is now 28.
ANSI/ASHRAE Standard 135.1-2023 (BACnet Testing Standard), was published in January 2023.
Addenda
Published addenda and addenda currently out for public review can be found here.
Interpretation Requests
Interpretations to Standard 135, 135.1 and any published addenda can be found here.
Errata
Errata to Standard 135, 135.1 and any published addenda can be found here.