Got this issue dude.
Warning from https://repo.packagist.org: You are using an outdated version of Composer. Composer 2.0 is now available and you should upgrade. See https://getcomposer.org/2
Using version ^0.3.2 for the-turk/flarum-mathren
./composer.json has been updated
Loading composer repositories with package information
Warning from https://repo.packagist.org: You are using an outdated version of Composer. Composer 2.0 is now available and you should upgrade. See https://getcomposer.org/2
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Installation request for the-turk/flarum-mathren ^0.3.2 -> satisfiable by the-turk/flarum-mathren[0.3.2].
- Conclusion: remove flarum/core v0.1.0-beta.15
- Conclusion: don't install flarum/core v0.1.0-beta.15
- the-turk/flarum-mathren 0.3.2 requires flarum/core >=0.1.0-beta.10 <0.1.0-beta.14 -> satisfiable by flarum/core[v0.1.0-beta.10, v0.1.0-beta.11, v0.1.0-beta.11.1, v0.1.0-beta.12, v0.1.0-beta.13].
- Can only install one of: flarum/core[v0.1.0-beta.10, v0.1.0-beta.15].
- Can only install one of: flarum/core[v0.1.0-beta.11, v0.1.0-beta.15].
- Can only install one of: flarum/core[v0.1.0-beta.11.1, v0.1.0-beta.15].
- Can only install one of: flarum/core[v0.1.0-beta.12, v0.1.0-beta.15].
- Can only install one of: flarum/core[v0.1.0-beta.13, v0.1.0-beta.15].
- Installation request for flarum/core (locked at v0.1.0-beta.15, required as ^0.1.0) -> satisfiable by flarum/core[v0.1.0-beta.15].
Installation failed, reverting ./composer.json to its original content.