Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
As noted by @mdahlhausen every release can introduce a change in results due to bug fixes or other improvements. Every local install of EnergyPlus includes a "changelog.html" file in the install root folder that lists all new features, defects repaired, and other changes for that release. The change lists are also posted on the EnergyPlus github release pages.
For a case like this, determine the specific release where the change appears by incrementing the file one version at time. Then consult the changelog for that release.
In this case, the file is quite simple, so I can guess that the change has to do with a bug fix related to BSDF (complex) fenestration. Stepping through the releases shows that the change occurred with version 8.8. Looking at the v8.8 changelog shows this related to BSDF:
6245 Improved Airflow Calculations for BSDF window types:
This version of EnergyPlus introduces improved version of airflow calculations for BSDF window type. It also include several bugfixes . . . Depending on shading construction and surface properties, results can be significantly different from previous version (especially in cases when front and back surface emissivity of shading layer is different.
Given that, I would trust the v8.9 results more than v8.5.
