About the name of the versions


In the version 3.9.8, we find some Breaking Changes. And I think the name is not the most apropiate following the current circunstancies. For future releases I believe we could use Semantic Versioning 2.0.0. http://semver.org/


Given a version number MAJOR.MINOR.PATCH, increment the:

MAJOR version when you make incompatible API changes,
MINOR version when you add functionality in a backwards-compatible manner, and
PATCH version when you make backwards-compatible bug fixes.

Additional labels for pre-release and build metadata are available as extensions to the MAJOR.MINOR.PATCH format.

Semantic Versioning Specification (SemVer)

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119.

  1. Software using Semantic Versioning MUST declare a public API. This API could be declared in the code itself or exist strictly in documentation. However it is done, it should be precise and comprehensive.

  2. A normal version number MUST take the form X.Y.Z where X, Y, and Z are non-negative integers, and MUST NOT contain leading zeroes. X is the major version, Y is the minor version, and Z is the patch version. Each element MUST increase numerically. For instance: 1.9.0 -> 1.10.0 -> 1.11.0.

  3. Once a versioned package has been released, the contents of that version MUST NOT be modified. Any modifications MUST be released as a new version.

  4. Major version zero (0.y.z) is for initial development. Anything may change at any time. The public API should not be considered stable.

  5. Version 1.0.0 defines the public API. The way in which the version number is incremented after this release is dependent on this public API and how it changes.

  6. Patch version Z (x.y.Z | x > 0) MUST be incremented if only backwards compatible bug fixes are introduced. A bug fix is defined as an internal change that fixes incorrect behavior.

  7. Minor version Y (x.Y.z | x > 0) MUST be incremented if new, backwards compatible functionality is introduced to the public API. It MUST be incremented if any public API functionality is marked as deprecated. It MAY be incremented if substantial new functionality or improvements are introduced within the private code. It MAY include patch level changes. Patch version MUST be reset to 0 when minor version is incremented.

  8. Major version X (X.y.z | X > 0) MUST be incremented if any backwards incompatible changes are introduced to the public API. It MAY include minor and patch level changes. Patch and minor version MUST be reset to 0 when major version is incremented.

  9. A pre-release version MAY be denoted by appending a hyphen and a series of dot separated identifiers immediately following the patch version. Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-]. Identifiers MUST NOT be empty. Numeric identifiers MUST NOT include leading zeroes. Pre-release versions have a lower precedence than the associated normal version. A pre-release version indicates that the version is unstable and might not satisfy the intended compatibility requirements as denoted by its associated normal version. Examples: 1.0.0-alpha, 1.0.0-alpha.1, 1.0.0-0.3.7, 1.0.0-x.7.z.92.

  10. Build metadata MAY be denoted by appending a plus sign and a series of dot separated identifiers immediately following the patch or pre-release version. Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-]. Identifiers MUST NOT be empty. Build metadata SHOULD be ignored when determining version precedence. Thus two versions that differ only in the build metadata, have the same precedence. Examples: 1.0.0-alpha+001, 1.0.0+20130313144700, 1.0.0-beta+exp.sha.5114f85.

  11. Precedence refers to how versions are compared to each other when ordered. Precedence MUST be calculated by separating the version into major, minor, patch and pre-release identifiers in that order (Build metadata does not figure into precedence). Precedence is determined by the first difference when comparing each of these identifiers from left to right as follows: Major, minor, and patch versions are always compared numerically. Example: 1.0.0 < 2.0.0 < 2.1.0 < 2.1.1. When major, minor, and patch are equal, a pre-release version has lower precedence than a normal version. Example: 1.0.0-alpha < 1.0.0. Precedence for two pre-release versions with the same major, minor, and patch version MUST be determined by comparing each dot separated identifier from left to right until a difference is found as follows: identifiers consisting of only digits are compared numerically and identifiers with letters or hyphens are compared lexically in ASCII sort order. Numeric identifiers always have lower precedence than non-numeric identifiers. A larger set of pre-release fields has a higher precedence than a smaller set, if all of the preceding identifiers are equal. Example: 1.0.0-alpha < 1.0.0-alpha.1 < 1.0.0-alpha.beta < 1.0.0-beta < 1.0.0-beta.2 < 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0.


Also, about the changelog there is a good post too: http://keepachangelog.com/en/0.3.0/


We have a changelog:



Re: SEMVER, it’s my intention for us to move to proper semantic versioning starting with 4.0.


Just one detail @ned. I think for bug fixes we could use an extra number. Like that:


MAJOR version when you make incompatible API changes,
MINOR version when you add functionality in a backwards-compatible manner, and
PATCH version when you make backwards-compatible
EXTRA bug fixes.

Because backwards-compatible together with bug fixes. i think is a bad idea. Some times with wordpress a backwards-compatible is not really a backwards-compatible once you put together with more plugins. If we have 4 digit, we can be really sure, and update of the EXTRA number means nothing will happen to the site and we do not need to check or review for breaks of the site.


This is never the case. You always need to test. If I’m using semver, I’m using semver.


One question. SEMVER increase the number of the mayor really fast. What about https://github.com/exadra37-versioning/explicit-versioning ?


No, we’re going to use semver.


I’m of the school “head of master branch is the release.” In the era of continuous integration this is often the norm.

I’m OK with semantic versioning because it is a widely accepted standard. Pressbooks should follow it. It’s good.

On the flip side versioning is not stability. It only communicates intention and best efforts.

Today, for example, Pressbooks released version 3.9.9. As far as we knew we didn’t intentionally break anything. We followed Semantic Versioning to communicate this fact. Unfortunately it turns out that if you were running MPDF then, surprise, it was a breaking change.

We acted quickly to resolve the issue. The code was available and it was collaboratively diagnosed. I think that’s what matters.

Versioning was the theatre.

Best regards,


both options allow to inform about a break. the difference is the first digit in semver increases to fast. In the end is not possible to understan what is about the version.

Explicit versioning or a system of 4 digits where the breack is the digit number 2, allow more human information in the code.

MS Windows, they use easy numbers XP, 7, 8, 10… is easy to have information about each version. If window would use semver, windows 7 would be (as example) 51 and 52 and 53 and 54 and 55 and 56 and 57 and… it is hard to remember what is about each version in such way if a collection of 6 or 12 versions are the same as version 7.1 and 7.2 and 7.3 and 7.4 … much easy to uderstand.

as example, pressbooks 4 increase because we have a breacking change and then pb 4.1 because we have a new fresh theme for the root theme and book theme … looks like is the same but is like a new web site. To offer a first digit for “marketing purposes” or really really big chagnes or UX changes makes easy to track the evolution of the code.

As long as we use one aproach with some sense and documentation in the back, I do not really care because I´m day by day taking care of PB and reading the news you tell me. But after some research about semver, I believe is not the best approach for a community project.

semver is good for an android developer, is good for developers that do not need integrations with other programs or customers (developers customers). In such way the developer can track the changes because nobody cares about the version. But if some people must integrate te code, semver is not the best option in my opinion. But better than nothing.


An important point I think you are missing here is that once the Pressbooks Book and Pressbooks Publisher themes are moved into their own releases as of Pressbooks 4.0, they will be (semantically) versioned separately. So an update to Pressbooks Publisher won’t increase the version of Pressbooks (the plugin), just its own version. Also I hope you are considering the fact that we haven’t been following semantic versioning until this point, so your past experience with breaking changes in Pressbooks is not a good predictor of future events.


Also, not to be picky, but I don’t think this is the best example of a clear versioning pattern.