Exchange Feature Flighting | Exchange Site Reliability
Microsoft Exchange Updates
Microsoft Exchange Updates are the following:
SU = Security Update released monthly. These include security updates and changes required to protect the servers.
CU = Cumulative Update released biannually, meaning 2 times every year. These include new features as well as all security updates. Sometimes referred to as Feature Updates.
The release schedule used to be every March and September with the naming convention being "YearMonth" in YYMM format. So, for example, 1903 stands for March 2019 and 1909 stands for September 2019.
But release schedules are hard to keep and often slip past the release timeframe. "It's ready when it's ready!" As a result, the release timeframes were moved from 1-month time-window to 6-months time-window with the naming convention being "YearHalf" in YYH1 format. So, for example, 24H1 stands for the first half of the year of 2024 and 24H2 stands for the second half of 2024.
Note that even though this update category contains features, everyone wanted to stay away from using the FU abbreviation.
HU = Hotfix Update released as needed. These include "oh crap" fixes for a specific issue/problem/scenario.
Feature Flighting - Microsoft Exchange Update for Subscription Edition (SE)
Feature Flighting is an update process by which the feature is included in the CU but it is disabled by default. Then the servers check every hour to an online endpoint (officeclient.microsoft.com) controlled by Microsoft product team. This Microsoft team can enable/disable features on a global stage when they feel ready.
This is done by RINGS or LEVELS or RING-LEVELS or RING-NUMBERS or STAGES-OF-RELEASE or RELEASE-STAGE. It depends on who you talk to.
Stages
The RING numbers are 0, 1, 2 and they correspond to different stages of release. The proper term is Software Development Life Cycle (SDLC).
- Ring -2 (as in T minus 2) / Alpha / Canary / Insider Preview: presumably, this ring stage is hidden from public view.
- Ring -1 (as in T minus 1) / Beta / Preview: presumably, this ring stage is only available to select trusted teams.
- Ring 0 (as in Ring Zero) / Release Candidate (RC): this ring stage is available to everyone so the feature can be tested in their on-prem environment.
- Ring 1 (as in Ring One) / Production: released globally. This is the default setting.
- Ring 2 (as in Ring Two) / Admin must enable feature manually.
Prereq
To see if your servers can reach the Microsoft Exchange Flight Endpoint, use:
test-netconnection officeclient.microsoft.com -p 443
To see if your servers can reach the Microsoft Cert Trust List, use:
test-netconnection ctldl.windowsupdate.com -p 80