A SAMSON Extension that worked yesterday may not load after a platform update—or an extension update may not appear when you expect it. The reason is often not the extension’s own release number, but the version of the SAMSON SDK used to build it.
Understanding that distinction can help molecular modelers identify what changed, avoid unnecessary troubleshooting, and know when updating SAMSON is relevant.
There are two version numbers to keep straight
SAMSON has a public version, such as 2026 R1, and an internal version shared by SAMSON and its SDK, such as 11.0.0. The internal version follows a major.minor.patch format. In the usual release cycle, a major change can break backward compatibility, a minor release adds functionality compatibly, and a patch release contains a compatible bug fix.
An extension also has its own version number, but that number describes updates to the extension itself. It does not tell SAMSON whether the extension can run. For compatibility, SAMSON checks the SDK version used to build the extension.
The compatibility check, in practical terms
The documentation describes an extension as compatible when the SDK and SAMSON have the same major version, and the SDK’s minor version is lower than SAMSON’s minor version. For instance, an extension built with SDK 1.6.4 can be loaded by SAMSON 1.7.8: the major versions match, and the SDK minor version is lower.
This makes the SDK version especially useful when diagnosing a problem. If an extension will not load, check the SDK version it was built with and compare it with the internal SAMSON version—not just the extension’s own release number or SAMSON’s public year-and-release label.
Why an extension update may not arrive
SAMSON can automatically update extensions when a newer compatible version is available on SAMSON Connect and an internet connection is available. For example, if SAMSON is 1.7.8 and an extension update was built with SDK 1.6.4, the update is compatible under the documented rule and can be installed during startup.
But automatic updating is not a way around a major-version mismatch. If SAMSON remains at 1.7.8 while an extension’s newly published build targets SDK 2.0.0, SAMSON will not update to that build. It can keep the previously installed compatible extension instead. In that situation, updating SAMSON may be necessary before using the newer extension build.
A quick troubleshooting checklist
- Find SAMSON’s internal version. The public version and internal SDK version are different labels.
- Find the SDK version used to build the extension. The extension’s own version number is not the compatibility number.
- Compare major versions first. The documented compatibility rule requires them to match.
- Check the minor versions. The SDK minor version must be lower than SAMSON’s under the stated rule.
- For automatic updates, check connectivity and availability. A compatible newer extension must be published on SAMSON Connect, and an internet connection must be available.
One final distinction: during the beta period, when the major version is zero, the minor version takes the role of the major version. A non-backward-compatible update increments the minor version; compatible functionality and fixes increment the patch version.
For the current public release and more details on versioning and extension compatibility, see the SAMSON versioning documentation.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.