Will This Extension Load? A Quick Guide to SAMSON Version Compatibility

A molecular modeling session can depend on more than the structure on screen. It may also rely on SAMSON Extensions for particular tasks. So when an extension is missing or not updated, a practical first question is: Was it built for a compatible version of SAMSON?

The version labels can be confusing because SAMSON has two systems. The public release name—for example, 2026 R1—is different from the internal version used by SAMSON and its Software Development Kit (SDK), such as 11.0.0. Extension compatibility is determined using the internal SDK version, not the public release label.

A simple compatibility check

Compare the SDK version used to build the extension with SAMSON’s internal version. In the standard version format, major.minor.patch, the documented compatibility rule is:

  • The SDK and SAMSON must have the same major version.
  • The SDK’s minor version must be lower than SAMSON’s minor version.

The patch numbers do not determine compatibility under this rule. For example, an extension built with SDK 1.5.2 can be loaded by SAMSON 1.7.8: the major numbers match, and the SDK minor number, 5, is lower than SAMSON’s, 7. SDK 1.3.5 is also compatible with SAMSON 1.7.8.

By contrast, SDK 1.8.5 is not compatible with SAMSON 1.7.8. Its minor version is higher. The extension may depend on functionality introduced in SDK 1.8 that SAMSON 1.7 does not yet contain. A matching major number by itself is therefore not enough: check the minor numbers too.

Why this matters in practice

If an extension does not load, its own version label is not the compatibility test SAMSON uses. Each extension has an independent major.minor.patch version, but SAMSON checks the SDK version used to build it. The extension’s version number can tell you that the extension has changed; it does not, by itself, tell you whether it can run in your installed SAMSON version.

This distinction is useful when comparing an extension update with your installation. Imagine your SAMSON version is 1.7.8 and the installed extension was built with SDK 1.5.2. If a newer extension build using SDK 1.6.4 becomes available, that SDK version meets the compatibility rule for SAMSON 1.7.8. SAMSON can update the extension automatically during startup when an internet connection is available.

But if SAMSON remains at 1.7.8 and a new extension is built with SDK 2.0.0, it is not compatible under the documented rule. SAMSON will not update to that extension build. Updating SAMSON can matter not only for SAMSON features and fixes, but also for access to extension builds made for newer SDK versions.

A quick troubleshooting checklist

  1. Find SAMSON’s internal version; don’t rely only on its public release name.
  2. Check the SDK version used to build the extension.
  3. Confirm that the major versions match and that the SDK minor version is lower than SAMSON’s.
  4. Remember that automatic extension updates require an internet connection and a compatible extension version to be available.
  5. Keep SAMSON updated when practical, especially if you need newer extension builds.

These checks help separate a compatibility issue from a confusing difference in version labels. For the complete versioning policy and additional examples, see the SAMSON versioning documentation.

Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.

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