Module Fears About Latest Vassal

I am completely ignorant of programming and computer technical terms. I am running Vassal 3.6.8. My favorite modules are Wellington’s Victory (TSR) and Into the Woods (GMT). If I update to the latest Vassal, will these still work?

Yes. Unless you have very specific knowledge of a module’s unwitting reliance on a bug fixed in the releases since 3.6.8, you should have every confidence that modules you’re using now with no issues will work fine in the latest release.

There are only extremely isolated sets of circumstances where it makes sense to resist using the latest release. 99% of the time you’ll see no impact or actually benefit from bug fixes.

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Also, you don’t have to uninstall previous versions of Vassal. Just keep 3.6.8 installed until you’re sure everything is OK.


There is a simple paradigm to understand that will not only answer this now, but in the future.

Vassal uses a 3 field versioning scheme for configuration control:

  1. A change to the last field should never cause a problem
  2. A change to middle field may cause a problem for some modules, but most should be ok (e.g., 3.6 removed some deprecated features, so modules that used those may break)
  3. A change the first digit is likely to cause problems for a fair number of modules.

This versioning scheme is pretty common for software, not just Vassal. Of course, this also relies on developers who correctly follow the paradigm (i.e., don’t remove features in Maintenance updates).

Developers can probably enhance my explanation…

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That’s an accurate description. We don’t add features at 3.x.y which would not work at 3.x.z, for z < y. Everything on the same minor version is notionally feature compatible.

If you upgrade but remain on the same minor version number, and you find that something has stopped working, there are only two possibilities: We have fixed a bug on which a module you’re using relied, or we introduced a bug inadvertently. In the former case, the module needs to be updated; in the later case, we will fix the bug in a subsequent release (but only if we’re made aware of the bug).

If you upgrade to a version with a larger minor version number, there may be new features. New features tend not to be backwards compatible, simply because earlier versions don’t contain code for the new features. Old modules should continue working, as they necessarily cannot be using any features which didn’t exist when they were made.

I have a related question.
Do you think version 4 of Vassal, when it is released, will cause all or most version 3.x.x modules to no longer work?

They might not (probably won’t?) work as-is, but conversion of VASSAL 3.x modules to the future file format is a stated goal.

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