[Bug]: Default C# / .NET buildpack is very outdated

[Xymanek]

Error Message and Logs

Building docker image started.
To check the current progress, click on Show Debug Logs.
[CMD]: docker exec w8k400c888kwkscks0okk88s bash -c 'nixpacks build -c /artifacts/thegameplan.json --cache-key 'x4ogsk0wksso0oo0ckw88os0' --no-error-without-start -n x4ogsk0wksso0oo0ckw88os0:feecb5deb9b3d95478ef6d3b1b860160ec7fcb0e /artifacts/w8k400c888kwkscks0okk88s -o /artifacts/w8k400c888kwkscks0okk88s'
╔═════════════════════ Nixpacks v1.33.0 ═════════════════════╗
║ setup      │ dotnet-sdk, curl, wget                        ║
║────────────────────────────────────────────────────────────║
║ install    │ dotnet restore                                ║
║────────────────────────────────────────────────────────────║
║ build      │ dotnet publish --no-restore -c Release -o out ║ 

Later:

> [ 7/10] RUN  dotnet restore:
2.782   Determining projects to restore...
2.847 /nix/store/0f43yfx91hg74bcp66qkbp97zv3ln27i-dotnet-sdk-6.0.413/sdk/6.0.413/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.TargetFrameworkInference.targets(144,5): error NETSDK1045: The current .NET SDK does not support targeting .NET 9.0.  Either target .NET 6.0 or lower, or use a version of the .NET SDK that supports .NET 9.0. 

.NET 6 has reached EOL in Nov 24: https://versionsof.net/core/

Steps to Reproduce

1. Create a blank ,NET 9 project
2. Attempt to deploy it

Example Repository URL

No response

Coolify Version

v4.0.0-beta.397

Are you using Coolify Cloud?

No (self-hosted)

Operating System and Version (self-hosted)

AlmaLinux 9.5

Additional Information

No response

[Xymanek]

Thanks to @Cinzya on discord for pointing out that this is a nixpack issue: railwayapp/nixpacks#1246

According to that thread it's possible to get the support by adjusting nixpkgsArchive value (railwayapp/nixpacks#1246 (comment)) though there appear to be stability issues with latest nixpacks.

Discord ref: https://discord.com/channels/459365938081431553/1311114127292235816/1352718041603117178

[peaklabs-dev]

This is a Nixpacks issue, as support told you correctly. You can simply update the nixpkgsArchive to a version that supports the updated dependencies you need.