Gravity Forms Signature Add-On was updated to version 2.4, from version 2.3. Changelog:

• Added drag and drop support to the field button in the form editor (GF 1.9).
• Added Spanish (es_ES) translation.
• Updated POT localization file.
• Updated GFSignature::maybe_save_signature() to public.
• Updated signature script to latest version.
• Fixed a fatal error if Browser.php was already included by another plugin.
• Fixed an issue with the delete signature confirmation message.
• Fixed signature appearing as a black image in some email clients.
• Fixed issue a JavaScript error in the form editor in some languages.
• Fixed issue with causing mixed content warning when Force SSL was enabled in the admin.
• Fixed issue when multiple Html2RGB() functions were defined.
• Fixed issue with folder path causing signature not to be saved correctly on same servers.