Erlang application upgrade file
File type: Various data file
The appup file extension belongs to the Erlang programming language and the Erlang/OTP application platform.
An .appup file contains the instructions and version information used to upgrade or downgrade an Erlang application.
File type category:
Various data file
Date updated: October 2, 2026
Erlang/OTP, originally developed at Ericsson, is a programming language and runtime platform for building concurrent, distributed, fault-tolerant and massively scalable soft real-time systems. It is available on Windows and other platforms.
An .appup file is a text file that describes how an application changes between releases. It typically lists the application versions concerned and the code update, process state conversion or other instructions needed for a release handler to perform a hot upgrade or downgrade.
The file belongs with the corresponding Erlang application and is normally stored alongside its application metadata and compiled modules.
An .appup file is an Erlang text file rather than a standalone executable. On Windows, it can be viewed in a plain-text or Erlang-aware editor.
To use the file, place it in the application's expected directory, normally alongside its compiled modules, and run the Erlang/OTP release tooling or release handler. The tooling reads the file as part of an application upgrade.
There is no useful general-purpose conversion format for an .appup file. Its contents are version-specific Erlang upgrade and downgrade instructions, so converting them to another format would remove their purpose.
When an application changes, the file should be edited or regenerated as Erlang/OTP appup data, with its version entries and upgrade instructions updated to match the new release.
Software applications that handle other tasks involving appup files:
Microsoft Windows
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