Contact Form 7 v5.1 dropped support for reCaptcha v2 along with December 2018.
At that point you will just need to head to this plugins settings page to tell the website to use reCaptcha v2..
Once installed and configured it should be reCaptcha functionality you are used to in previous versions of Contact Form 7..
Using the left-hand admin in Contact Form 7 subpages click.
Once API keys are set, the 2 has been selected in the plugin settings, all tags will be replaced with the Google reCaptcha on all forms...
If you doing upgrade from version of Contact Form to the version you will need to re-add the Version API keys using the method.
That being said you can set the usage to default and it will use Contact Form reCaptcha Version API...
Setup Integration following instructions from Contact Form documentation.
If you have added the Version 2 keys and you still do not see reCaptcha show up on your forms please check the following.
Interested in development.., check out SVN repository, or subscribe to the development log by RSS...
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