# Release versioning

You can define how the next release number will be generated when creating a release.

:::div{.hint}
We recommend using [SemVer](/docs/packaging-applications/create-packages/versioning#semver) as the versioning scheme for releases in Octopus.
:::

Within a project, click **Settings ➜ Release Versioning**:

:::figure
![Release Versioning](/docs/img/releases/images/release-versioning.png)
:::

You can use variables from the project (un-scoped or scoped only to a channel). In addition, some special variables are provided - example:

```text
1.2.#{Octopus.Version.NextPatch}-pre
```

These special variables take the form:

```text
Octopus.Version.(Last|Next)(Major|Minor|Patch|Build|Revision|Suffix)
```

If you are using channels, channel-specific special variables are also available:

```text
Octopus.Version.Channel.(Last|Next)(Major|Minor|Patch|Build|Revision|Suffix)
```

Version components from other channels in the project can be referenced using the channel name as the index:

```text
Octopus.Version.Channel[ChannelName].(Last|Next)(Major|Minor|Patch|Build|Revision|Suffix)
```

The channel name can also be used (generally as part of the suffix):

```text
Octopus.Release.Channel.Name
```

The version can also include Octopus *semantic version mask* characters i and c referring to the **incremented** and **current** values of the version, respectively. For example:

```text
2.1.c.i
```

Finally, date fields can be also be used, for example:

```text
#{Octopus.Date.Year}.#{Octopus.Date.Month}.#{Octopus.Date.Day}
```

These take the form:

```text
Octopus.Date.(Day|Month|Year|DayOfYear)
Octopus.Time.(Hour|Minute|Second)
```

## Complex expressions

The full power of the [Octopus variable syntax](/docs/projects/variables/variable-substitutions/#complex-syntax) (powered by [Octostache](https://github.com/OctopusDeploy/Octostache)) is available in version templates.  In particular, [conditional expressions](/docs/projects/variables/variable-substitutions/#conditionals) can be used to model some complex scenarios.

### Example: Date with incrementing revision

A relatively common versioning scheme is:

```text
YEAR.MONTH.DAY.REVISION
```

where `REVISION` starts at 0 each day and increments with each release. i.e. The releases on one day might be `2020.10.2.0`, `2020.10.2.1`, `2020.10.2.2` ... and the following day may be: `2020.10.3.0`, `2020.10.3.1` etc.

This can be achieved using the following expression:

```text
#{Octopus.Date.Year}.#{Octopus.Date.Month}.#{Octopus.Date.Day}.
#{if Octopus.Date.Day==Octopus.Version.LastPatch | Format Int32 D2}
#{Octopus.Version.NextRevision}
#{else}
#{if Octopus.Version.LastRevision!=0}
0
#{else}
#{Octopus.Version.NextRevision}
#{/if}#{/if}
```

:::div{.warning}
This example is no longer recommended for production workloads due to the potential for unexpected version
conflicts arising from inconsistencies between date formats. The mask-based alternative provided below
should be preferred.
:::

```text
#{Octopus.Date.Year}.#{Octopus.Date.Month}.#{Octopus.Date.Day}.i
```

The `i` mask character increments the previous release's revision component by one on every release. Note
that the revision component will reset whenever any part of the date changes from the previous release.