So typical of the PowerShell team - I go off to a lovely yoga class, and they ship something important. Namely the first release candidate for what is to become PowerShell 7. In a perfect world, RC1 would be the final release, except as in any sufficiently large software product there are bound to be a few minor issues that need to be ironed out. But the product is functionally complete, what you see now is that is going to ship (minus any bugs). AND - this release is fully supported in production which is important for many enterprise customers.
You can read more here: https://devblogs.microsoft.com/powershell/announcing-the-powershell-7-0-release-candidate/. The team should be congratulated on the clear and concise manner with which they communicate, both on the blog and on social media.
So why do RC1 and PowerShell 7 matter? Does anyone care about a release candidate of a scripting language? I see two main reasons for IT Pros and larger enterprises to begin to transition, or at the very least start the planning for that transition.
First, it is a significant upgrade to PowerShell itself. It feels more significant than going from Windows PowerShell V2 to V3. There are a host of new features and some tremendous performance improvements, especially for very large workloads. So if you are processing all the AD computer or user accounts in a large multinational or testing connectivity to a large number of hosts using Test-Connection you are going to love PowerShell 7.
Today, many (most?) larger organisations manage production systems using suites of large and complex PowerShell scripts. For such organisations, the performance improvements alone probably justify the switch. Not mention how many little things are added that make it a joy to use.
A second reason is that Windows PowerShell is feature complete. It is not going to be improved or extended. So what works today is going to carry on being supported. All the improvements have been added to PowerShell 7. That also means leaving behind the ISE. A great tool, now in effect replaced by VS Code which is also a huge improvement.
As with any major change, there are a few things that just do not work - and won't work in PowerShell 7 when it ships early in 2020. There is a great backwards compatibility story for most of the commands that are not explicitly built using .NET Core. In the main, they work pretty well. But there are a few Windows Server modules whose command do not work and are highly unlikely to work at RTM. Two modules I'm aware of at the moment are Best Practices and the WSUS module. The WSUS module will need a major redevelopment and at this time there is no word from the team (but feel free to vote on this suggestion: https://windowsserver.uservoice.com/forums/304618-installation-and-patching/suggestions/39267028-wsus-server-should-be-manageable-using-powershell).
So if you are not doing so already, start using RC1.