I'm creating a server on old version 1381 and wanted to get some plugins from the site, but all plugins have error.
How can I convert an updated plugin into an outdated version?

On the plugin page you should be able to find an "Updates" tab, you click on it and all other versions will be shown and you can download whichever one you want. Just bear in mind the plugin author/maintainer is unlikely to be supporting old versions of the plugin.

Please keep in mind that old versions and piracy are not supported here, and get ally old versions of plugins are not supported as well. You can find old versions in the History as mentioned above, but generally you'd be on your own if trying to do what you are doing.