If you’ve ever built or installed a SAMSON Extension and found that it mysteriously fails to load, you’re not alone. One of the most common and frustrating issues for molecular modelers and developers alike is extension incompatibility—especially when you’re juggling multiple versions of SAMSON and its SDK. Let’s clear up how version compatibility works, and help you avoid version mismatches that keep your tools from working.
Understanding the Compatibility Rules
SAMSON follows a semantic versioning policy for both itself and its Software Development Kit (SDK). That means the version format used is major.minor.patch. The rules for determining whether an Extension is compatible with your installed version of SAMSON are simple but strict:
- The major version number of the SDK used to build the Extension must match the major version number of your installed SAMSON.
- The minor version number of the SDK used for the Extension must be less than or equal to the minor version of SAMSON.
That’s it. But getting this wrong—even by one minor version—means your Extension simply won’t load at startup. SAMSON always checks these version numbers to maintain stability and prevent runtime errors from missing functionality.
A Practical Example
Let’s say your SAMSON version is 1.7.8. In this case, extensions built with SDK versions like 1.3.5 or 1.7.7 will load just fine because:
- The major version (
1) matches - The SDK’s minor version is less than or equal to your SAMSON’s minor version (
7)
However, an extension built with SDK version 1.8.5 will not load. Even though the major version is the same, the minor version of the SDK (8) exceeds the minor version of SAMSON (7), indicating that the extension might be relying on features your version of SAMSON doesn’t yet support.
What You Can Do
If one of your extensions isn’t loading, check the SDK version it was built with (this is usually listed in the extension’s docs or metadata), and compare it with your installed SAMSON version’s SDK version. If the minor version is too high, you have two options:
- Update your SAMSON installation to a newer version that matches or exceeds the SDK’s minor version.
- Use an earlier version of the Extension built with a compatible SDK.
How SAMSON Helps
The good news is that SAMSON automatically updates Extensions during startup, as long as:
- You’re connected to the Internet
- The update is compatible with your current SAMSON SDK version
This system ensures that you typically have the most recent compatible version of an Extension without manual downloads. However, if an Extension update is built using a higher major SDK version—for example, after a major SAMSON release like 2.0.0—SAMSON will no longer update that Extension for users still using 1.x versions, to avoid compatibility issues.
Final Tip
To avoid compatibility headaches, it’s best to let SAMSON update itself automatically. Regular updates ensure that you always run a version that is compatible with newer Extensions while benefiting from the latest improvements.
Want to learn more about version compatibility? Visit the full documentation page here.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON at https://www.samson-connect.net.