New version with banner has side effect on other mkdocs plugin, at least mike

[jylenhofdecat]

Context

With the release of https://github.com/squidfunk/mkdocs-material/releases/tag/9.7.2
you added a warning banner that has side effect on mike mkdocs plugin I use

You're using standard stdout to print the banner and this banner is added to its own output...

Bug description

On mike, I use mike list to list versions managed by mike... and now in its output in addition of its standard output there is the warning which breaks my script qui parses the json output

│ ⚠ WARNING – MkDocs 2.0 is incompatible with Material for MkDocs 
 │  
 │  MkDocs 1.x is unmaintained. We recommend switching to Zensical, our 
 │  new static site generator, as soon as possible. We're providing an 
 │  analysis of the situation in this article: 
 │  
 │  https://squidfunk.github.io/mkdocs-material/blog/2026/02/18/mkdocs-2.0/ 

[ 
 { 
 "version": "v0.2.1", 
 "title": "v0.2.1", 
 "aliases": [] 
 }, 
 { 
 "version": "v0.1.0", 
 "title": "v0.1.0", 
 "aliases": [] 
 } 
]

Related links

• Reporting a bug

Reproduction

See output

Steps to reproduce

Update the mkdocs-material with last version

Browser

No response

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• I have attached links to the documentation, and possibly related issues and discussions.
• I assure that I have removed all customizations before submitting this bug report.
• I have attached a .zip file with a minimal reproduction using the built-in info plugin.

[squidfunk]

Thanks for reporting. We can certainly print to stderr, if that would resolve the situation. Other than that, the banner is a must, since we must raise awareness about the impending changes to the MkDocs ecosystem. The rationale is explained here.

[jylenhofdecat]

That was my first test after got this problem to try separating stdout and stderr, so it could help...

After reading code, it seems there's also a variable I can set to avoid this problem : NO_MKDOCS_2_WARNING=1
Perhaps this information should be in the release notes or even in the warning itself, so people affected could use this quickly also

[squidfunk]

That was my first test after got this problem to try separating stdout and stderr, so it could help...

Feel free to send a PR, if this resolves the situation.

[squidfunk]

Fixed in 70dee38. The message will now print to stderr.

[connesy]

@squidfunk Can this be released as a patch? It's affecting our builds as well.

[squidfunk]

Of course! Changes have been released as part of 9.7.3 a minute ago.