.NET Core 3.1 offers a small number of fixes over .NET Core 3.0 and is a long-term supported (LTS) release, which will be supported for three years.
.NET Core can be installed on RHEL 7 with the usual:
$ yum install rh-dotnet31
We recommend users of .NET Core 2.2 and 3.0 migrate their applications to .NET Core 3.1.
Note that .NET Core 2.2 will be end-of-life on December 23, 2019. .NET Core 3.0 will be end-of-life on March 3, 2019. The previous LTS release, .NET Core 2.1, is supported until August 21, 2021.