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The definitive check is the installed extension’s manifest.json file. Open edge://extensions to identify the extension and its ID, then open that extension’s manifest and read manifest_version: 2 means Manifest V2 and 3 means Manifest V3. The release field named version is a different value and cannot tell you which manifest format the extension uses.
On Windows, the installed file is usually under the active Edge profile’s Extensions directory. A warning on the extensions page is useful context, but because Microsoft says warnings are shown to some users, no warning is not proof that every extension is on V3.
What to check: manifest_version, not version
Every Edge extension package has a manifest.json file. Microsoft describes this file as the extension’s JSON blueprint and lists manifest_version as a required field in its manifest file format documentation.
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Look for a line like one of these:
"manifest_version": 2"manifest_version": 3manifest_version: 2: the extension uses Manifest V2.manifest_version: 3: the extension uses Manifest V3.
Do not use a value such as 4.2.1 to make this determination. A field named version is the extension’s release number; it can change independently of the manifest format. An extension released as version 4.2.1 could still be V2 or could already be V3.
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These are separate checks. The release number tells you which publisher package you have, while manifest_version tells you which Edge extension format that package declares. Record both when documenting an installation.
Fastest decision path
- Open
edge://extensionsand identify the extension by name and ID. - Determine whether it is store-installed, unpacked, or managed.
- For a store-installed package, open the matching ID and version folder in the active profile’s
Extensionsdirectory. - For an unpacked package, open the source directory that was loaded into Edge.
- Read the top-level
manifest.jsonand search formanifest_version. - Record
2or3; do not substitute the extension’s release number or warning status.
This route separates identification from verification: the extensions page helps you find the right package, and the manifest supplies the definitive format value.
Check an installed extension on Windows
This method gives a definitive answer for the package currently installed in a particular Edge profile. You need permission to read the profile files on the computer.
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One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware match- Open the extensions manager. In Edge, enter
edge://extensionsin the address bar and press Enter. - Find the extension. Match the extension by name. If several extensions have similar names, record its ID as well. Microsoft’s documentation on alternative extension distribution explains that the ID and extension version are visible on this page after a packed extension is loaded.
- Open the profile’s Extensions folder. The common Windows location is
%LOCALAPPDATA%MicrosoftEdgeUser Data<profile>Extensions. Microsoft Q&A gives the equivalent pattern asC:UsersusernameAppDataLocalMicrosoftEdgeUser DataprofilefolderExtensions; replace the account name and profile-folder name with the values on your computer. - Match the ID directory. Inside
Extensions, locate the folder whose name matches the ID shown for the extension inedge://extensions. If Edge has more than one profile, check the profile that contains the extension you identified. - Open the installed version folder. The ID folder normally contains a directory named for the installed extension version. Open that directory and locate
manifest.json. - Read the manifest. Open
manifest.jsonin a text editor and search formanifest_version. The value2is V2; the value3is V3.
The version-directory name and the version property in the file can help you identify which release you opened, but neither replaces reading manifest_version. If an extension has several version directories, use the one that Edge currently has loaded rather than an old directory left behind after an update.
How to make sure you opened the active copy
Start with the ID and release version displayed for the extension in edge://extensions. Use the ID to select the correct directory, then compare the version-directory name with the displayed release. If more than one directory remains, inspect the directory corresponding to the currently reported release. Keep the profile name with your notes, because another Edge profile can contain a different copy of the same extension.
What to do if you cannot find the folder
- Confirm that you are looking under the same Edge profile in which the extension is installed. Each profile has its own extension storage.
- Use the extension ID from
edge://extensions, not only the display name; folder names are based on the ID. - Check that you opened the version subdirectory, because the
manifest.jsonyou need is inside the installed version directory. - If the computer is managed and you cannot browse the profile, ask an administrator for a copy of the installed manifest or use the policy information described below. A policy can control whether V2 runs, but it does not change the value recorded in the extension’s manifest.
- If Edge has just updated the extension, refresh the extensions page and repeat the ID-and-version match before recording a result.
Check an unpacked or locally developed extension
An unpacked extension does not use a store-installed copy in the profile’s normal extension directory. Microsoft’s sideloading guidance describes loading an extension from a directory that contains its source files, including manifest.json.
- Identify the local source directory that was selected when the extension was loaded.
- Open that directory in a text editor or code editor.
- Open its top-level
manifest.json. - Read
manifest_versionexactly as you would for a packaged extension.
Do not infer the format from the fact that Developer mode is enabled, from the extension’s name, or from its release number. Developer mode only enables development features; it does not indicate V2 or V3. If the source directory has been edited since it was loaded, note that you are checking the current source manifest, not necessarily an older packaged copy.
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What edge://extensions can and cannot tell you
The extensions page is the best starting point, but it is not a complete manifest inspector.
| Information | Available on edge://extensions? |
What it means |
|---|---|---|
| Extension name | Yes | Use it to identify the installed item. |
| Extension ID | Yes for a loaded packed extension | Use it to match the correct directory in the profile’s Extensions folder. |
| Extension release version | Yes | This is the package’s version; it does not reveal V2 or V3. |
manifest_version |
Not shown as a definitive field | Read the installed package’s manifest.json to determine the format. |
| Whether a warning is displayed | Sometimes | A warning is a migration signal, not a substitute for reading the manifest. |
For example, seeing an extension version of 4.2.1 does not answer the V2 question. Conversely, an extension with no warning may still require a direct manifest check because Microsoft’s published wording says deprecation warnings are shown to some users.
Can the warning on the extensions page prove an extension is V2?
A V2 deprecation warning is strong evidence that Edge has identified the extension as affected, so it is a useful prompt to investigate. It is not the most reliable record of the package format, however. Microsoft’s current migration timeline says warnings are scheduled to appear for some users on the Manage extensions page starting in mid-September 2026. Because the rollout is not stated as universal, the absence of a warning cannot establish that every installed extension is V3.
For a per-extension answer, open that extension’s installed manifest.json and read manifest_version. Treat the warning as a notification and the manifest field as the definitive check for the package you actually have. A warning also does not tell you whether a newer package is available or whether your organization permits the extension to continue running; those are separate questions.
Edge’s Manifest V2 migration timeline
Microsoft’s timeline page, updated September 15, 2026, lists these milestones. They describe Microsoft’s published plan; they do not determine the format of any particular copy installed on your computer.
| Date or period | Published milestone | Practical meaning for checking an extension |
|---|---|---|
| July 2022 | Partner Center and the Microsoft Edge Add-ons website stopped accepting new Manifest V2 extensions. | A newly submitted extension is expected to be V3, but an older V2 extension can remain installed. |
| August 2026 | Partner Center began displaying a Manifest V2 deprecation warning for extensions that still use V2. | Publisher-facing warnings may appear even when an end user has not seen one. |
| Mid-September 2026 | Warnings were scheduled to appear for some users on Edge’s Manage extensions page and at the Microsoft Edge Add-ons website. | Warning visibility depends on the rollout and user population; no warning is not proof of V3. |
| Early 2027 | Manifest V2 deprecation is expected to begin for enterprise customers. | Managed organizations should inventory extensions before that stage rather than waiting for a block. |
| Other dates | Some dates, including when Edge Add-ons will stop accepting updates to extensions that remain on V2, are still listed as not yet determined. | Do not assume a specific update cutoff unless Microsoft publishes it. |
Microsoft advises developers whose extensions remain on V2 to migrate to V3 and submit the migrated version through Partner Center. A migration notice does not prove that the developer has completed that work or that your installed copy has updated; the local manifest remains the relevant evidence.
See Microsoft’s Timeline for migrating to Manifest V3 for the dated plan and later revisions.
Managed devices: policy can affect whether V2 runs
On an organization-managed computer, two separate questions often get confused:
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manifest_versionin the package. - Is Edge allowed to run that format? Check the organization’s policy and the resulting browser behavior.
Microsoft’s ExtensionManifestV2Availability policy has four modes:
| Policy mode | Effect described by Microsoft |
|---|---|
Default |
Uses the browser’s default behavior. |
Disable |
Disables Manifest V2 extensions. |
Enable |
Allows Manifest V2 extensions. |
EnableForForcedExtensions |
Allows force-installed V2 extensions while other V2 extensions are disabled. |
The policy is supported on Windows and macOS starting with Edge 123. Microsoft lists Android and iOS as unsupported for this policy. A policy setting can therefore explain why one V2 extension works on a managed device while another is disabled, but it cannot turn a V2 manifest into a V3 manifest.
If your organization controls the browser, ask the administrator which policy mode applies and whether the extension is force-installed. Do not change enterprise policy merely to bypass a warning; use the manifest check to document the extension format and follow the organization’s migration process.
Developer mode and access restrictions
You do not need Developer mode simply to open a local manifest.json file. However, an administrator can control whether users may enable Developer mode on edge://extensions. Microsoft’s ExtensionDeveloperModeSettings policy documents that managed control for supported Windows and macOS versions 128 and later.
If Developer mode is unavailable, you can still:
- Use the extension’s visible ID and version on
edge://extensionsto identify it. - Inspect the installed package in the profile’s
Extensionsdirectory when you have file access. - Ask an administrator or support team to perform the manifest check.
Developer mode is useful for loading an unpacked project, but it is not evidence that an extension uses either manifest version.
Choosing the right checking method
| Method | Convenience | Certainty | Access needed | Best use |
|---|---|---|---|---|
Read manifest.json in the installed package |
Moderate | Definitive for that installed package | Access to the local profile files | Audits, troubleshooting, and migration records |
| Inspect an unpacked extension’s source manifest | High if you own the source directory | Definitive for that source copy | Access to the development directory | Local development and sideloaded extensions |
Use edge://extensions alone |
High | Not definitive for V2 versus V3 | Access to Edge | Finding the name, ID, version, and warning status |
| Check organization policy | Low for end users | Explains availability, not manifest format | Administrator or policy-report access | Managed-device failures and forced installations |
For a quick personal check, the extensions page followed by the profile manifest is usually the shortest path. For an audit, use the same manifest-based evidence for every item and record the profile, ID, release, manifest value, and date. For a managed fleet, add the applicable policy mode and whether each item is force-installed.
Troubleshooting common mistakes
You read the extension’s release number
Return to the file and search for the literal key manifest_version. A release such as 4.2.1 belongs to the separate version field and cannot answer the question.
You opened the wrong profile
Edge profiles have separate extension directories. Match the extension ID shown in the profile’s edge://extensions page to the ID folder under that profile’s Extensions directory.
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You opened an old version directory
An update can leave more than one version directory. Open the directory corresponding to the version Edge currently reports as installed, then read that directory’s manifest. Do not report the format of an older copy as the format of the active copy.
You cannot find manifest.json
Verify that you are inside the version subdirectory, not only the ID directory. For an unpacked extension, use the source directory from which it was loaded instead of the store-installed path.
The page shows no warning
Use the direct manifest check. Microsoft’s timeline limits the warning rollout to some users, so a clean-looking extensions page does not establish that all installed extensions are V3.
The extension is disabled after a policy change
Check whether the organization uses ExtensionManifestV2Availability. In EnableForForcedExtensions mode, a force-installed V2 extension can remain allowed while other V2 extensions are disabled. The policy explains the behavior; manifest_version still identifies the package format.
The manifest contains formatting you do not recognize
Do not rely on the position of the field or on surrounding permissions. Search for the exact key name, then read its numeric value. If the file cannot be opened or the value is missing, ask the extension owner or administrator for the correct package rather than guessing from the warning or release number.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.A concise audit procedure for several extensions
If you need to document a whole profile, use the same evidence standard for every item instead of relying on warnings or release numbers.
- Open
edge://extensionsand make a list of each extension’s name, ID, and displayed release version. - For each ID, locate the matching directory under the relevant profile’s
Extensionsfolder. - Open the active version directory and record the exact
manifest_versionvalue frommanifest.json. - Mark any item with
manifest_version: 2for migration or replacement according to your organization’s schedule. - For managed computers, record the applicable V2 availability policy separately so an allowed or blocked state is not mistaken for the manifest format.
- Recheck after an extension update. A publisher can ship a new package whose manifest format differs from the previous release.
A useful inventory row contains: extension name, ID, Edge profile, displayed release version, manifest value, whether the extension is unpacked or packaged, warning status, policy mode if managed, and check date. This makes it possible to distinguish a changed package from a changed browser policy.
Keep the extension ID, installed release number, manifest value, profile, and check date together in your inventory. That combination identifies what was actually installed rather than what a publisher may have submitted or what a warning rollout may display.
Frequently asked questions
Can I tell from the extension’s version number?
No. The displayed release, such as 4.2.1, corresponds to the package’s version field. Only manifest_version identifies V2 or V3.
Is a warning required for a V2 extension?
No. Microsoft says warnings are scheduled for some users, so warning coverage is not universal. Read the installed manifest for a definitive answer.
Does no warning mean the extension is V3?
No. It may mean the warning has not reached that user or that the page is not displaying it. Absence of a warning is not proof of manifest_version: 3.
Where is the manifest on Windows?
For a packaged extension, look under %LOCALAPPDATA%MicrosoftEdgeUser Data<profile>Extensions, then open the directory matching the extension ID and its installed version. For an unpacked extension, use the source directory that was loaded.
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No. Developer mode is not required to open a local manifest. Administrators can restrict Developer mode, but that restriction does not prevent a user with file access from reading the package.
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Can enterprise policy change a V2 extension into V3?
No. ExtensionManifestV2Availability controls whether V2 extensions are allowed, disabled, or allowed only when force-installed. The manifest’s value remains the format identifier.
Why might one V2 extension work while another is disabled?
A managed device may use EnableForForcedExtensions, which allows force-installed V2 extensions while disabling other V2 extensions. Check both the manifest and the organization’s policy.
Does the migration timeline prove my installed copy has been updated?
No. The dates describe Microsoft’s rollout plan. A publisher’s migration notice or a store milestone does not prove that the package in your profile has changed; inspect its current manifest.json.
Bottom line
Use edge://extensions to identify an extension, then inspect that extension’s manifest.json. The field manifest_version is the answer: 2 is Manifest V2 and 3 is Manifest V3. Warnings, release numbers, Developer mode, and policy behavior provide context, but none replaces reading the manifest for the installed package.
Frequently Asked Questions
What field proves an Edge extension uses Manifest V2?
The installed package’s manifest.json is definitive. A value of "manifest_version": 2 means Manifest V2; 3 means Manifest V3.
Can an extension version such as 4.2.1 identify V2 or V3?
No. That is the extension’s release number in the separate version field. It does not identify the manifest format.
Does a missing warning prove an extension is V3?
No. Microsoft’s warning rollout is described as applying to some users. Check manifest_version directly.
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Use %LOCALAPPDATA%MicrosoftEdgeUser Data<profile>Extensions, match the extension ID, open the installed version directory, and read manifest.json.
What if the extension is unpacked?
Open the source directory loaded into Edge and inspect its top-level manifest.json instead of searching for a store-installed copy.
Can enterprise policy change the manifest format?
No. ExtensionManifestV2Availability controls whether V2 extensions may run; it does not change the manifest value.
Do I need Developer mode for this check?
No. Developer mode is useful for loading unpacked projects but is not required to read a local manifest file.
The Bottom Line
Find the extension in edge://extensions, match its ID and active version, and read manifest_version in manifest.json. 2 is V2; 3 is V3. Treat warnings, release numbers, and policy settings as context only.
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