Have you ever updated or downloaded a SAMSON Extension and then wondered why it just… doesn’t load? You’re not alone. For many molecular modelers using the SAMSON platform, ensuring that Extensions work properly can be confusing — especially when a dependency mismatch is silently blocking the Extension from launching.
The issue often boils down to something that sounds trivial but is critically important: version compatibility between SAMSON and the Software Development Kit (SDK) used to build the Extension.
How version compatibility works in SAMSON
Whenever SAMSON starts, it checks every loaded Extension’s SDK version against its own internal SDK version. According to SAMSON’s semantic versioning policy, compatibility follows these rules:
- The major version of the Extension SDK must be identical to the SAMSON SDK major version.
- The minor version of the Extension SDK must be less than or equal to the SAMSON SDK minor version.
Let’s go through an example. If your SAMSON version is 1.7.8, then an Extension built with SDK version 1.6.4 or 1.5.2 will load just fine. But if you try loading one built with SDK 1.8.5 — boom 💥 — that Extension will be rejected. Why? Because its minor version number is higher than that of your SAMSON installation (1.8 vs 1.7).
Why this matters for you
If you’re developing tools or simulating molecular systems with SAMSON, your workflow may depend on specific Extensions. Understanding how these version numbers interact lets you avoid the frustration of silent incompatibility errors. You’ll also be better prepared to troubleshoot when Extensions don’t start as expected.
So what can you do?
Keep SAMSON updated. SAMSON includes an automatic update system that ensures compatible Extensions are downloaded when new versions appear on SAMSON Connect. If the Extension you’re trying to run was built for a newer SDK version, you’ll need to update SAMSON itself, since backward compatibility in SDK minor versions is not assumed.
However, note that SAMSON will not automatically update to a newer major SDK version. This helps avoid compatibility issues in reverse: loading an Extension that relies on functions your current SAMSON version doesn’t offer.
Version numbers of Extensions: what they mean (and what they don’t)
Each SAMSON Extension has its own major.minor.patch version number. This separate versioning is intended for user awareness — it tracks updates within the Extension itself. But SAMSON does not use this versioning when checking compatibility. Instead, only the SDK version used to build the Extension is considered.
This means you might see an updated Extension version number (say, 2.1.0), but if it was built with a newer major SDK than your current SAMSON installation, it still won’t load — and SAMSON will stick to the last compatible version it downloaded.
Practical takeaway
If your Extension doesn’t load, check the SDK version it was built with, and compare it to your SAMSON version’s SDK. Chances are there’s a mismatch in either the major or minor version numbers.
You can also avoid surprises by frequently checking for SAMSON updates and reading the release notes, especially for Extensions under active development.
To learn more about how SAMSON manages versioning and ensures Extension compatibility, check the official documentation here.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON at www.samson-connect.net.