If you have a question that belongs in this general news FAQ, please email HEC.ResSim@usace.army.mil and we will try to publicly respond to questions as they come in.

Will there be a ResSim 3.6?

No, ResSim 3.5.1 is the end of that line of code, unless there is a critical issue that demands a patch because the user cannot upgrade to 4.0.

When do we expect to release ResSim 4.1, 4.2, etc.? 

We completed ResSim 4.1 in February 2026 and will make the release official in March.  It has a few improvements to the Operation Support Interface.

We would like to continue to make new releases at this faster pace.  As of March 2026, we are working on a timeline or scope for ResSim 4.2

Are there summaries shared somewhere about adjustments to controlling scripts and State Variables due to API changes?

The best source for this information would be the CWMS documentation:  

https://www.hec.usace.army.mil/confluence/cwmsdocs/cmrkit/3.3.1/scripting/transition-from-hecjavadev-to-hecmonolith-major-scripting-changes

Use the documentation version selector to find all the documentation related to scripting changes.  This information changes with each release, but it all may be relevant, depending on what you're working on.

What are the best sources for the latest and greatest ResSim news or discussions?

Currently these are your options.  Please don't hesitate to send us your suggestions.