While this has been mentioned in a few places I thought it prudent to also create a blog post. Asterisk 13 and Asterisk 17 have entered security fix only status. What does this mean, though?
When bug fixes and changes are put up for review they will no longer be done against Asterisk 13 and Asterisk 17. Instead those two versions will only receive fixes as a result of filed security issues, for an additional year. Once this year is up those versions will no longer receive any changes and will be considered end of life. This means Asterisk 13 will be end of life on October 24th, 2021 and Asterisk 17 will be end of life October 28th, 2021.
If you are still on either version then you should start making a plan for upgrading to a supported version. Asterisk 16 and Asterisk 18 are both long term supported releases with Asterisk 18 being supported for a longer duration. Asterisk 16 will enter security fix only status on October 9th, 2022 while Asterisk 18 will enter security fix only status as of October 20th, 2024.
As always I urge you to keep track of these dates using the Asterisk Versions wiki page.