Microsoft have announced that they will stop providing security updates and tech support for .Net 4, 4.5 and 4.5.1. To ensure that PE is running on a patched and supported platform the targeted version of the .Net framework in use for V9.3 will be .Net 4.5.2. This change does not have any functional impact but will require that servers are on a supported patch level from Microsoft. This will affect all servers PE is installed upon – both SQL and the Web servers. Further details can be found from Microsoft: https://blogs.msdn.microsoft.com/dotnet/2015/12/09/support-ending-for-the-net-framework-4-4-5-and-4-5-1/
This will only affect clients moving to the latest version of 9.3.