Could not install the release version 2.1.0

[gstars271]

I tried to install the package 2.1.0 into my project .Net Framework 4.5.2, but it occurred error: 'Install-Package : Could not install package 'SlackBotMessages 2.1.0'. You are trying to install this package into a project that targets '.NETFramework,Version=v4.5.2', but the package does not contain any assembly references or content files that are compatible with that framework'

Then I installed the previous version (2.0.1) and it's ok. Is there a way to fix this issue?