> For the complete documentation index, see [llms.txt](https://bryan-guner.gitbook.io/my-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bryan-guner.gitbook.io/my-docs/untitled-1/content/semantic-versioning.md).

# Semantic Versioning

If there's one great thing in Node.js packages, it's that they all agreed on using Semantic Versioning for their version numbering.

The Semantic Versioning concept is simple: all versions have 3 digits: `x.y.z`.

* the first digit is the major version
* the second digit is the minor version
* the third digit is the patch version

When you make a new release, you don't just up a number as you please, but you have rules:

* you up the major version when you make incompatible API changes
* you up the minor version when you add functionality in a backward-compatible manner
* you up the patch version when you make backward-compatible bug fixes

The convention is adopted all across programming languages, and it is very important that every `npm` package adheres to it, because the whole system depends on that.

Why is that so important?

Because `npm` set some rules we can use in the `package.json` file to choose which versions it can update our packages to, when we run `npm update`.

The rules use those symbols:

* `^`
* `~`
* `>`
* `>=`
* `<`
* `<=`
* `=`
* `-`
* `||`

Let's see those rules in detail:

* `^`: It will only do updates that do not change the leftmost non-zero number. If you write `^0.13.0`, when running `npm update`, it can update to `0.13.1`, `0.13.2`, and so on, but not to `0.14.0` or above. If you write `^1.13.0`, when running `npm update`, it can update to `1.13.1`, `1.14.0` and so on, but will not update to `2.0.0` or above.
* `~`: if you write `~0.13.0`, when running `npm update` it can update to patch releases: `0.13.1` is ok, but `0.14.0` is not.
* `>`: you accept any version higher than the one you specify
* `>=`: you accept any version equal to or higher than the one you specify
* `<=`: you accept any version equal or lower to the one you specify
* `<`: you accept any version lower to the one you specify
* `=`: you accept that exact version
* `-`: you accept a range of versions. Example: `2.1.0 - 2.6.2`
* `||`: you combine sets. Example: `< 2.1 || > 2.6`

You can combine some of those notations, for example use `1.0.0 || >=1.1.0 <1.2.0` to either use 1.0.0 or one release from 1.1.0 up, but lower than 1.2.0.

There are other rules, too:

* no symbol: you accept only that specific version you specify (`1.2.1`)
* `latest`: you want to use the latest version available