At the time of writing, Fedora ships Mono 4.8. This can be quite inconvenient when you want to work on C# 7.x projects, since C# 7.0 support was added since Mono 5.0. So why doesn’t Fedora ship Mono 5.x? I’m not sure, but it looks like it will remain like that for a while. On ticket redhat#1436896 you can see what the progress is on Fedora/Mono 5.

Mono provides an EPEL repository for CentOS and Fedora, which contains the latest stable version of the Mono framework. Great, let’s try to use that. After I added the repository (as described by Mono) and ran the command sudo dnf install mono-complete, I stumbled upon a problem as described by mono/mono#11937. libgif.so.4 was not installed and could not be provided by any package in my installed repositories. Apparently, it was provided by the package compat-giflib, which was removed from the main Fedora repositories since Fedora 29. Luckily, rpmfind provided Fedora 28’s old compat-giflib RPM, which I installed:

wget https://rpmfind.net/linux/fedora/linux/releases/28/Everything/x86_64/os/Packages/c/compat-giflib-4.1.6-1.fc28.x86_64.rpm
sudo dnf install compat-giflib-4.1.6-1.fc28.x86_64.rpm

After retrying to install mono-complete, I succeeded. Mono 5.18 was installed!

So I returned to my C# IDE (Jetbrains Rider) to stumble upon my next problem. Since Mono 5.x, xbuild is deprecated and Rider stopped supporting it for Mono 5.x. After searching the web, I eventually found this Jetbrains ticket: RIDER-23088. In this ticket was being told that one should use msbuild. After checking my system, I found that msbuild was not installed. So I searched through dnf and found that I could run:

sudo dnf install msbuild

This resolved my Rider problem, after reinitializing my project.

In the end this cost me about 2-3 hours of research, with one goal: get Entity Framework to connect to my Postgresql database.