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

For example, if you have a Houdini 20.5 license, you will be able to open Houdini 20.5 and older (20.0, 19.5, 19.0 etc...).

• When installing older versions of Houdini, do not install the License Server component of the old version.
• If you do overwrite the latest sesinetd server binary, reinstall the latest Houdini version again.

Old installers may be found in the public folder on our public FTP server: ftp.sidefx.com
You may use the standard FTP ports to connect from your FTP client.

To use FTP, you can download use any FTP client. One popular client is FileZilla.