I tend to stick to "recommended" versions:
┌──────────────────────────────────GHCup──────────────────────────────────┐
│ Tool Version Tags Notes │
│─────────────────────────────────────────────────────────────────────────│
│✔✔ GHCup 0.1.30.0 latest,recommended │
│─────────────────────────────────────────────────────────────────────────│
│✗ Stack 2.15.7 latest │
│✗ Stack 2.15.5 recommended │
│✗ Stack 2.15.3 │
│─────────────────────────────────────────────────────────────────────────│
│✗ HLS 2.9.0.1 latest │
│✗ HLS 2.9.0.0 │
│✗ HLS 2.8.0.0 │
│✔✔ HLS 2.7.0.0 recommended │
│✗ HLS 2.6.0.0 │
│─────────────────────────────────────────────────────────────────────────│
│✗ cabal 3.12.1.0 latest │
│✔✔ cabal 3.10.3.0 recommended │
│✗ cabal 3.6.2.0-p1 │
│─────────────────────────────────────────────────────────────────────────│
│✗ GHC 9.10.1 latest,base-4.20.0.0 │
│✗ GHC 9.8.2 base-4.19.1.0 hls-powered,2024-02-23│
│✗ GHC 9.6.6 base-4.18.2.1 │
│✗ GHC 9.6.5 base-4.18.2.1 │
│✔✔ GHC 9.4.8 recommended,base-4.17.2.1 hls-powered │
│✗ GHC 9.2.8 base-4.16.4.0 hls-powered │
│✗ GHC 9.0.2 base-4.15.1.0 │
│✗ GHC 8.10.7 base-4.14.3.0 │
│✗ GHC 8.8.4 base-4.13.0.0 │
│✗ GHC 8.6.5 base-4.12.0.0 │
│✗ GHC 8.4.4 base-4.11.1.0 │
└─────────────────────────────────────────────────────────────────────────┘
However, it looks like I'm having trouble building on Hackage, and maybe it's because Hackage is using a newer GHC than the one GHCup tells me is the recommended version.
So what's the relevance of "recommended", and where does it come from?
The GHCup installation page is the first result when you use their page search for "recommended". It tells you:
GHCup has two main channels for every tool: recommended and latest. By default, it installs recommended.
latest follows the latest release of every tool, while recommended is at the discretion of the GHCup maintainers and based on community adoption (hackage libraries, tools like HLS, stackage support, etc.) and known bugs.
So it's whatever their maintainers recommend.