# Stop incompatible protocol changes

**URL:** <https://community.letsencrypt.org/t/stop-incompatible-protocol-changes/155413>\
**Category:** Help\
**Created:** [July 9, 2021, 7:46am UTC](https://community.letsencrypt.org/t/stop-incompatible-protocol-changes/155413 "2021-07-09T07:46:08Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![\_az](https://avatars.discourse-cdn.com/v4/letter/_/22d042/32.png) [@\_az](https://community.letsencrypt.org/u/_az)\
**Post date:** [July 9, 2021, 8:03am UTC](https://community.letsencrypt.org/t/stop-incompatible-protocol-changes/155413/3 "2021-07-09T08:03:42Z")

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HTTP 405 sounds like it might be this protocol change: [ACME v2 - Scheduled deprecation of unauthenticated resource GETs](https://community.letsencrypt.org/t/acme-v2-scheduled-deprecation-of-unauthenticated-resource-gets/74380).

Though technically, it was a change to the draft protocol; the final RFC8555 ACME protocol has always had this requirement.

The change was announced in 2018 and there was a grace period until November 2020 to make the transition.

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_[View the full topic](https://community.letsencrypt.org/t/stop-incompatible-protocol-changes/155413)._