More detailed instructions for updating old extensions are available at [[Updating your Extension for 1.0]]. Also check the [https://inkscape.gitlab.io/extensions/documentation/ extension (<code>inkex</code>) API documentation] and the [https://gitlab.com/inkscape/extensions stock extensions repository] for finding comparable extensions. If you have questions about extension development, you can join us in our [https://chat.inkscape.org/channel/inkscape_extensions extension development chat channel].
More detailed instructions for updating old extensions are available at Updating your Extension for 1.0. Also check the extension (inkex) API documentation.