Maybe the part about not having a valid header has to do with the code not including a license designation, which appears to be required.
I activated the plugin but can’t use it because in place of the buttons that are supposed to appear below the Publish box the following message appears:
Warning: in_array() expects parameter 2 to be array, string given in /home/fairmark/public_html/wp-content/plugins/duplicate-and-merge-posts/admin/duplicate-post.php on line 108
I went to settings, selected the box to exclude posts and the message went away (and stayed away when I went back to settings and deselected posts).
The valid header issue has been updated in 1.0.4
Will look into the other issue
The PHP warning is also fixed. Will release a plugin version update soon.
It shouldn’t halt any functionality for the time being though
