openHAB newbie here 
Been playing with 2.5 for a while in a test environment and comfortable with it (hardware setup, config, scripting, etc.), now coming to roll the hardware out in the house and wondering whether I should continue to use 2.5, or is 3 close enough to first RC for me to make the jump and configure the production system using that?
Will be running on a Raspberry Pi 4, using Z-Wave devices.
Jim
The first RC should come out tomorrow. Release should be in a week.
As for whether to jump on OH 3 now or not, you’ll have to decide. All software has bugs on the first release. OH is no different. They may be important to you, they may not be.
I can say from my perspective, OH 3 is a huge improvement to the user experience and well worth spending the time to use.
Go straight to OH3 so you won’t know what you’re missing from 2.5 
Go straight to V3 since you don’t have your 2.5 setup in use. If you had a system in use that had no issues then that would be different. It’s better and a waste of time to
Learn V2 now. Just understand you may hit a bug in an addon if using something not used by other people often.
Watch and hit the like button on this video that shows what the differences are.
With a Release Candidate imminent, I’d also say to go to 3.
And while you’re at it, PLEASE bless us with your fresh perspective by contributing to the documentation. If something doesn’t make sense, ask questions or edit the wiki. If you need a concept or a step to be explained to you, odds are that someone else will need that, too. 
I wish I could like this result more than once!
However, I’ve already started tansitioning the wikis to GitHub fire inclusion in the docs so if you do make an edit, please also post a reply so I can include the edit too. As of this writing I’ve mve over everything up to the model tutorial. I hope to add another few more pages today.
Thanks for the replies, looks like it’s v3!
Note, however, there isn’t a Raspberry Pi image yet, so will have to wait for that 
Jim
No need to wait 
OpenHABian already has the option to install openhab3. Choose the openhab3 branch and then:
Hit the button and upgrde done!
Bespoke rules not working, so now to understand what needs to be changed.
Jim
The biggest change will be that Joda DateTime has been replaced with ZonedDateTime. Another change that is less likely to trip you up is that only one instance of any given rule is allowed to run at a time, no more cases where the same rule is running two or more instances at the same time.
