Add initial AppNet baseline release note

[Sanya Kochhar (SanyaKochhar)]

Summary

Adds the initial customer-facing release note for AppNet (Azure Kubernetes Application Networking), covering customer-impacting changes since March 2026. Added as a distinct top-level ## AppNet Release Notes section in CHANGELOG.md, separate from the asm-1-XX Istio add-on entries since AppNet is a distinct product.

Content

Announcements/retirements, bug fixes, and Istio component updates for AppNet. Region list and individual entries confirmed with owners in review.

[Mitch Connors (therealmitchconnors)]

I'm thrilled to see our first release notes!

Left a bunch of minor comments on ensuring consistent language, and not referencing internal implementation details.

Let's Go!

[Copilot]

Pull request overview

Adds the first customer-facing AppNet release note section to the top of CHANGELOG.md, intended to summarize customer-impacting changes since March 2026 and keep AppNet updates separate from the existing Istio-based service mesh add-on (asm-*) entries.

Changes:

• Adds a new top-level “AppNet Release Notes - 2026-08-05” section at the beginning of the changelog.
• Documents AppNet announcements/retirements and a set of customer-facing fixes.
• Adds an AppNet component update summary mapping AppNet versions to upstream Istio versions.

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

Suppressed comments (5)

CHANGELOG.md:5

• The product name in the AppNet intro looks incorrect/inconsistent with the PR description. AppNet is described elsewhere as “Azure Kubernetes Application Networking”, not “Azure Kubernetes Application Network”.

> Azure Kubernetes Application Network (AppNet) — initial release notes covering changes since March 2026. AppNet is in public preview.

CHANGELOG.md:24

• “treated as success” is ungrammatical here; it should be “treated as successful” (or similar).

* Fixed member deletion being stuck in a retry loop when the underlying cluster had already been removed; already-deleted resources are now treated as success.

CHANGELOG.md:33

• There’s a mismatch between the PR description’s “Content” section (which mentions Features/Behavioral changes like cascade delete, private cluster support, overlapping-CIDR support, and specific component versions such as 1.3→Istio 1.28.8 and 1.4→Istio 1.29.4) and what’s actually documented here (no Features/Behavioral changes sections, and the patch versions shown are 1.28.10 / 1.29.6). Please align either the changelog content or the PR description so reviewers and customers don’t get conflicting info.

* AppNet 1.3 has been updated to [Istio 1.28.10](https://istio.io/latest/news/releases/1.28.x/announcing-1.28.10/).
* AppNet 1.4 has been updated to [Istio 1.29.6](https://istio.io/latest/news/releases/1.29.x/announcing-1.29.6/).
* AppNet 1.5 (Istio 1.30) is now available, using [Istio 1.30.3](https://istio.io/latest/news/releases/1.30.x/announcing-1.30.3/).

CHANGELOG.md:19

• The “Bug fixes” section currently includes behavior changes (new join-time validation, CRD ownership conflict handling, and blocking resource moves). This makes the section misleading and also diverges from the PR description’s “Behavioral changes” category. Consider splitting these into a separate “Behavioral changes” section and leaving true fixes under “Bug fixes”.

### Bug fixes

* AppNet now validates cluster prerequisites at member-join time and returns a clear, actionable error when a cluster is missing a required add-on (Microsoft Entra / AAD or the Managed Gateway API) or is running an AKS Kubernetes version below the minimum supported version, instead of failing opaquely later.
* Clusters using AKS managed Gateway API no longer hit a CRD ownership conflict when joining a mesh; AppNet defers to the add-on-provided Gateway API CRDs.
* Moving AppNet resources across resource groups or subscriptions is now blocked, as these move operations are not supported for AppNet.

CHANGELOG.md:9

• This Learn URL includes a locale segment (/en-us/), but the rest of this changelog predominantly uses locale-less Learn links. Also, the sentence reads more clearly if split into “...and follow...”.

* The following AppNet versions have been retired and are no longer supported. If using self-managed upgrade mode, upgrade to a currently supported version (see [Component updates](#component-updates)) following the [AppNet upgrade guide](https://learn.microsoft.com/en-us/azure/application-network/upgrades#initiate-an-upgrade).

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

Suppressed comments (6)

CHANGELOG.md:5

• The PR description says this AppNet note includes sections for features, behavioral changes, and specific version-to-Istio mappings, but the changelog content currently only includes Announcements/retirements, Bug fixes, and Component updates (with different Istio patch versions). Please either add the missing sections/content or update the PR description so it matches what’s actually being added.

## AppNet Release Notes - 2026-08-05

> Azure Kubernetes Application Network (AppNet) — initial release notes covering changes since March 2026. AppNet is in public preview.

CHANGELOG.md:24

• Grammar: "treated as success" should be rephrased (for example, "treated as successful" or "treated as a success").

* Fixed member deletion being stuck in a retry loop when the underlying cluster had already been removed; already-deleted resources are now treated as success.

CHANGELOG.md:3

• This section is dated 2026-08-05 but is placed above the 2026-08-07 release notes, which breaks the descending-by-date ordering used elsewhere in this file and may confuse readers scanning for the latest entry. Consider moving this AppNet section below 2026-08-07 or updating the date/title to reflect its intended ordering/publication date.

## AppNet Release Notes - 2026-08-05

CHANGELOG.md:9

• The link to #component-updates is fragile because this file already contains multiple "Component updates" headings; if ordering changes, this anchor could start pointing at a different section. Prefer avoiding a global anchor here or using a unique heading/link target for the AppNet section.

* The following AppNet versions have been retired and are no longer supported. If using self-managed upgrade mode, upgrade to a currently supported version (see [Component updates](#component-updates)) following the [AppNet upgrade guide](https://learn.microsoft.com/en-us/azure/application-network/upgrades#initiate-an-upgrade).

CHANGELOG.md:17

• "Microsoft Entra / AAD" is unclear/slash-formatted for a customer-facing note and doesn’t follow the usual "spell out then acronym" pattern. Consider using "Microsoft Entra ID (Azure Active Directory (AAD))" (or similar) to make the prerequisite explicit and scannable.

* AppNet now validates cluster prerequisites at member-join time and returns a clear, actionable error when a cluster is missing a required add-on (Microsoft Entra / AAD or the Managed Gateway API) or is running an AKS Kubernetes version below the minimum supported version, instead of failing opaquely later.

CHANGELOG.md:27

• "AppLink" is introduced here without definition or a link, and it doesn’t appear elsewhere in this repo. For a customer-facing changelog, spell out what an AppLink is (or link to the AppLink documentation) on first mention.

* Fixed an issue where failed AppLink and member operations returned a generic error instead of the specific reason; actionable failures, such as joining a cluster already connected to another AppLink, now explain what went wrong and how to resolve it.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

Suppressed comments (2)

CHANGELOG.md:17

• Terminology is inconsistent within this section: this line uses “member-join” while later bullets use “member join”. For customer-facing release notes, please use one form consistently.

* AppNet now validates cluster prerequisites at member-join time and returns a clear, actionable error when a cluster is missing a required add-on (Microsoft Entra / AAD or the Managed Gateway API) or is running an AKS Kubernetes version below the minimum supported version, instead of failing opaquely later.

CHANGELOG.md:4

• This new AppNet section is dated 2026-08-05 but it appears before the 2026-08-07 release notes section. The rest of this changelog is in reverse-chronological order, so this placement breaks the date ordering and makes it harder to scan recent entries.

## AppNet Release Notes - 2026-08-05

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

Suppressed comments (4)

appnet-notes/2026-08-05.md:13

• This section heading should be H2 (not H3) under the file’s H1 title to keep a consistent Markdown hierarchy.

### Bug fixes

appnet-notes/2026-08-05.md:27

• This section heading should be H2 (not H3) under the file’s H1 title to keep a consistent Markdown hierarchy.

### Component updates

appnet-notes/2026-08-05.md:3

• PR description refers to AppNet as “Azure Kubernetes Application Networking”, but this note calls it “Azure Kubernetes Application Network”. Please align the terminology so readers don’t see two different product names (either update the PR description or adjust this line if “Networking” is the preferred name).

> Azure Kubernetes Application Network (AppNet) — initial release notes covering changes since March 2026. AppNet is in public preview.

appnet-notes/2026-08-05.md:5

• This file uses an H1 title, but section headings start at H3. To keep a consistent Markdown hierarchy (and match the release-note structure used elsewhere in the repo), use H2 for these top-level sections under the H1.

This issue also appears in the following locations of the same file:

• line 13
• line 27

### Announcements and retirements

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

Suppressed comments (2)

appnet-notes/2026-08-19.md:3

• The PR description says this release note was added as a top-level section in CHANGELOG.md, but the current change set only adds a standalone file under appnet-notes/ and CHANGELOG.md contains no "AppNet" section/content. Please either update the PR description to reflect the new location, or add the intended AppNet section/link in CHANGELOG.md so customers can discover these notes from the main changelog.

# AppNet Release Notes - 2026-08-19

> Azure Kubernetes Application Network (AppNet) — initial release notes covering changes since March 2026. AppNet is in public preview.

appnet-notes/2026-08-19.md:15

• This is customer-facing text, but it uses the internal acronym "AAD" and a slash ("Microsoft Entra / AAD") without defining the acronym. Consider spelling out the name once and using "or" to make this clearer and consistent with "AKS managed Gateway API" terminology used in the next bullet.

* AppNet now validates cluster prerequisites at member-join time and returns a clear, actionable error when a cluster is missing a required add-on (Microsoft Entra / AAD or the Managed Gateway API) or is running an AKS Kubernetes version below the minimum supported version, instead of failing opaquely later.

[Dian Yu (dyu1208)]

Approve with one suggestion

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

Suppressed comments (5)

appnet-notes/2026-08-19.md:13

• This section heading is an H3 under an H1, which skips a level and can hurt document navigation for assistive technologies. Use ## for top-level sections under the title.

### Bug fixes

appnet-notes/2026-08-19.md:27

• This section heading is an H3 under an H1, which skips a level and can hurt document navigation for assistive technologies. Use ## for top-level sections under the title.

### Component updates

appnet-notes/2026-08-19.md:5

• The document skips directly from an H1 (#) to an H3 (###). Heading level jumps can reduce accessibility for screen readers and makes the outline harder to navigate. Use ## for the main sections under the page title.

This issue also appears in the following locations of the same file:

• line 13
• line 27

### Announcements and retirements

appnet-notes/2026-08-19.md:7

• The Learn link includes a hard-coded locale (/en-us/), while the earlier Learn link in this doc is locale-neutral. Prefer locale-neutral Learn URLs for consistency and to avoid redirect/locale issues.

* The following AppNet versions have been retired and are no longer supported. If using self-managed upgrade mode, upgrade to a currently supported version (see [Component updates](#component-updates)) following the [AppNet upgrade guide](https://learn.microsoft.com/en-us/azure/application-network/upgrades#initiate-an-upgrade).

appnet-notes/2026-08-19.md:15

• "Microsoft Entra / AAD" is inconsistent with the term used elsewhere in this repo ("Microsoft Entra ID") and uses a slash that can be unclear in customer-facing docs. Consider using "Microsoft Entra ID (Azure AD)" for clarity and consistency.

* AppNet now validates cluster prerequisites at member-join time and returns a clear, actionable error when a cluster is missing a required add-on (Microsoft Entra / AAD or the Managed Gateway API) or is running an AKS Kubernetes version below the minimum supported version, instead of failing opaquely later.