A few important details:

The feature is specifically the “Require review from specific team” ruleset capability.
It was initially released as a preview feature before broader GA rollout on GitHub.com.
GHES tends to lag behind GitHub Enterprise Cloud in UI availability, even when the API schema already supports the feature.

So if you upgraded to 3.20.1 and still don’t see it in the ruleset UI, the most likely explanations are:

The feature is API-only or partially gated in GHES 3.20.x.
It may require a feature flag from GitHub Support.
It may not become fully UI-available until a later GHES release (possibly 3.21+).

You can verify whether your appliance actually supports it by querying or creating a ruleset through the REST API and checking whether the required_reviewers field is accepted. The GHES 3.20 REST docs explicitly document that field.

Changelog eka verify karala. Key finding: the GA announcement (February 17, 2026) only mentions GitHub.com — no explicit mention of GHES support, and GHES 3.20 GA itself was announced March 17, 2026 — after the feature GA. Hodai answer ekak liyanna puluwan: githubgithub

Answer (Copy karala GitHub eke post karanna):

I looked into this and can confirm what you're experiencing — here's the full picture:
The GA announcement doesn't explicitly mention GHES support.
The February 17, 2026 changelog announcing general availability of the required reviewer rule only references GitHub.com/Enterprise Cloud. GHES 3.20 itself went GA on March 17, 2026 — one month after the feature GA — which likely means the feature shipped to GHES 3.20 in some form, but the UI availability may lag behind.
Most likely explanations for not seeing it in 3.20.1:

UI-gated, API-available — The feature may exist in the REST API for GHES 3.20 but not yet be surfaced in the ruleset UI. You can test this by trying to create a ruleset via the API with the required_reviewers condition and see if it's accepted.
Feature flag required — Some GHES features ship in a gated state and need to be enabled by GitHub Support on your appliance. It's worth opening a support ticket at https://support.github.com/ and specifically asking whether the required-reviewer ruleset rule requires a feature flag on GHES 3.20.
Slated for 3.21 — If it's truly missing from the UI and the API, it may have missed the 3.20 cutoff and be targeting the next release.

Recommended next step:
Contact GitHub Enterprise Support directly — they can confirm whether the feature is available for your appliance version, whether a flag needs enabling, and what the GHES roadmap looks like for this feature. Enterprise support is at https://support.github.com/.