What type of issue is this?
Incorrect support data (example: BrowserX says "86" but support was added in "40")
What information was incorrect, unhelpful, or incomplete?
The compatibility table for the CSS writing-mode property does not reflect that the sideways value is now supported in Microsoft Edge. This information needs to be updated.
What browsers does this problem apply to, if applicable?
Chromium (Chrome, Edge 79+, Opera, Samsung Internet)
What did you expect to see?
I expected the compatibility table for the CSS writing-mode property to show that the sideways value is supported in Microsoft Edge.
Did you test this? If so, how?
The screenshot below shows the writing-mode: sideways-lr property applied in Microsoft Edge version 132.0.2957.115 (Official build) (64-bit). As you can see, the text (on the right) is correctly rotated and flows sideways, confirming support for this property.

Current version is: 132.0.2957.115 (Official build) (64-bit)
Can you link to any release notes, bugs, pull requests, or MDN pages related to this?
Microsoft Edge release notes: https://learn.microsoft.com/en-us/deployedge/microsoft-edge-relnote-stable-channel#site-compatibility-impacting-changes
Screenshot from the release notes:

Do you have anything more you want to share?
Current Compatibility Table:

The compatibility table currently indicates that sideways-lr and sideways-rl are not supported in Microsoft Edge.
MDN URL
https://developer.mozilla.org/en-US/docs/Web/CSS/writing-mode
MDN metadata
MDN page report details
- Query:
css.properties.writing-mode
- Report started: 2025-01-18T07:25:38.351Z
What type of issue is this?
Incorrect support data (example: BrowserX says "86" but support was added in "40")
What information was incorrect, unhelpful, or incomplete?
The compatibility table for the CSS writing-mode property does not reflect that the sideways value is now supported in Microsoft Edge. This information needs to be updated.
What browsers does this problem apply to, if applicable?
Chromium (Chrome, Edge 79+, Opera, Samsung Internet)
What did you expect to see?
I expected the compatibility table for the CSS writing-mode property to show that the sideways value is supported in Microsoft Edge.
Did you test this? If so, how?
The screenshot below shows the writing-mode: sideways-lr property applied in Microsoft Edge version 132.0.2957.115 (Official build) (64-bit). As you can see, the text (on the right) is correctly rotated and flows sideways, confirming support for this property.
Current version is: 132.0.2957.115 (Official build) (64-bit)
Can you link to any release notes, bugs, pull requests, or MDN pages related to this?
Microsoft Edge release notes: https://learn.microsoft.com/en-us/deployedge/microsoft-edge-relnote-stable-channel#site-compatibility-impacting-changes
Screenshot from the release notes:

Do you have anything more you want to share?
Current Compatibility Table:

The compatibility table currently indicates that sideways-lr and sideways-rl are not supported in Microsoft Edge.
MDN URL
https://developer.mozilla.org/en-US/docs/Web/CSS/writing-mode
MDN metadata
MDN page report details
css.properties.writing-mode