I agree with @Kevin.Herron on generally going to the newest version–with the caveat that I tend to wait a few days to see if any issues that would affect us come up in the forum (of course this doesn’t work if everyone does it ).
A couple other things you may need to consider are noted in this short thread:
In our case, we’re on 8.1.9 and waiting for 8.1.13 for the next upgrade due to the issue with default tag provider assumed in many paths on older projects and no urgent need for anything in 8.1.10-8.1.12.
The default name of the OPC Server no longer has a hyphen. Was “Ignition OPC-UA Server” but now is “Ignition OPC UA Server”
Alarm Notification Pipelines are now project scoped, so your tags should identify the path to the pipeline as GatewayName/ProjectName/PipelineName.
When you purposefully wanted to store a Bad Quality into the Tag Historian by using the quality value of 410 = “Disabled” (very helpful when you wanted to record data only when a system is running by using the expression function forceQuality(None,410)), the underlying dataintegrity value in the database would be 600. This made the Easy Chart display breaks in the trends even when interpolation is enabled and not selecting “Ignore Bad Quality”. It also displayed the tag as disabled which is helpful in knowing that no data is being stored at the moment. In 8.x the Tag Historian records a different dataintegrity value of 0 which is not interpreted as Bad Quality and no longer creates a break. Instead, you have to utilize the new expression function qualifiedValue(None,‘bad’,512) or 515 I think.