---
name: "relup"
section: "5"
platform: "linux"
package: "erlang-manpages"
version: "1:25.2.3+dfsg-1+deb12u4"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/relup"
---

# relup(5)

Release upgrade file

## NAME

relup - Release upgrade file

## DESCRIPTION

The *release upgrade file* describes how a release is upgraded in a running system.

This file is automatically generated by *systools:make\_relup/3,4*, using a release resource file (*.rel*), application resource files (*.app*), and application upgrade files (*.appup*) as input.

## FILE SYNTAX

In a target system, the release upgrade file is to be located in directory *$ROOT/releases/Vsn*.

The *relup* file contains one single Erlang term, which defines the instructions used to upgrade the release. The file has the following syntax:

```
{Vsn,
  [{UpFromVsn, Descr, Instructions}, ...],
  [{DownToVsn, Descr, Instructions}, ...]}.
```

- ***Vsn = string()*:**

  Current release version.

- ***UpFromVsn = string()*:**

  Earlier version of the release to upgrade from.

- ***Descr = term()*:**

  A user-defined parameter passed from the function *systools:make\_relup/3,4*. It is used in the return value of *release\_handler:install\_release/1,2*.

- ***Instructions*:**

  A list of low-level release upgrade instructions, see *[appup(5)](/appup/5.md)*. It consists of the release upgrade instructions from the respective application upgrade files (high-level instructions are translated to low-level instructions), in the same order as in the start script.

- ***DownToVsn = string()*:**

  Earlier version of the release to downgrade to.

## SEE ALSO

*[app(5)](/app/5.md)*, *[appup(5)](/appup/5.md)*, *[rel(5)](/rel/5.md)*, *[release\_handler(3erl)](/release_handler/3erl.md)*, *[systools(3erl)](/systools/3erl.md)*