Houdini is backwards compatible. Older versions of Houdini will run with the most recent license.

For example, if you have a Houdini 19.5 license, you will be able to open Houdini 19.5 and older (19.0, 18.5, 18.0 etc...).

• You need the latest License Server software and licenses to run both latest and older versions of Houdini.
• When installing older versions of Houdini, do not install the License Server component of the old version as it will overwrite the latest sesinetd binary.
• If you do overwrite the latest sesinetd server binary, reinstall the latest Houdini version again.

Old installers may be found on our public FTP server.