[Plugin: Related Posts by Tag] Bug: starts output before expected

When various functions are performed in the WP backend, a PHP error comes up saying output cannot be started because headers already sent. The ‘Related Posts by Tag’ plugin initiates output before WP is ready because of the way the author has used the <? ?> tags to wrap his code. Instead of using one set of tags, the author has used many throughout the code file. Anything outside of these tags is taken by PHP and output to the HTTP stream. The plugin file for version 1 contains several linebreaks after the last PHP close tag. If you are getting output already started errors, delete these linebreaks right up to the last PHP close tag. This will fix the error. Could the author please provide a fix for this bug for everyone else.

https://www.ads-software.com/extend/plugins/related-post-by-tag/