# 10. Package Description Format Specification History¶

Package descriptions need to specify the version of the specification they need to be interpreted in via the cabal-version declaration. The following list describes changes that occurred in each version of the cabal specification relative to the respective preceding published version.

Note

The sequence of specification version numbers is not contiguous because it’s synchronised with the version of the Cabal library. As a consequence, only even versions are considered proper published versions of the specification as odd versions of the Cabal library denote unreleased development branches which have no stability guarantee.

## 10.1. cabal-version: 3.6¶

• License fields use identifiers from SPDX License List version 3.10 2020-08-03

## 10.2. cabal-version: 3.4¶

• License fields use identifiers from SPDX License List version 3.9 2020-05-15

• Dependencies to sublibraries have to be specified explicitly, even for current package. This way you can have an internal library with the same name as some external dependency.

• Remove -any and -none syntax for version ranges Use >=0 and <0 respectively.

• default-language is optional. The Default value is to use the compiler’s default language.

• mixins field allow specifying a sublibrary.

## 10.4. cabal-version: 2.4¶

• Wildcard matching has been expanded. All previous wildcard expressions are still valid; some will match strictly more files than before. Specifically:

• Double-star (**) wildcards are now accepted for recursive matching immediately before the final slash; they must be followed by a filename wildcard (e.g., foo/**/*.html is valid; foo/**/bar/*.html and foo/**/**/*.html, foo/**/bar.html are all invalid). As ** was an error in globs before, this does not affect any existing .cabal files that previously worked.

• Wildcards now match when the pattern’s extensions form a suffix of the candidate file’s extension, rather than requiring strict equality (e.g., previously *.html did not match foo.en.html, but now it does).

• License fields use identifiers from SPDX License List version 3.2 2018-07-10

## 10.11. cabal-version: 1.16¶

Todo

this needs to be researched; there were only few changes between 1.12 and 1.18;