How to update the plugin?
Updating through FTP
Simply overwrite the plugin files with the new version files via FTP, then deactivate and activate back the plugin.
Updating via the WordPress Installer
Set the ‘Keep Settings’ to ON in the General Settings in the plugin’s admin page. Deactivate and delete the plugin, then install the new version as a new plugin (Add New). With turning on the ‘Keep Settings’ option, the plugin will keep the configuration datas, so you don’t have to set it up again.
Updating via the built-in Manual Plugin Updater
Navigate to the Update section under the Simple Signup admin page, then simply upload the new version ZIP file, then follow the instructions.