Using v2.1 of Narwhal Microblog on WordPress 5.2.4 and PHP v7.2 I get the following error:

Warning: Use of undefined constant posthasteForm - assumed 'posthasteForm' (this will throw an Error in a future version of PHP) in /home/public_html/wp-content/plugins/narwhal-microblog/narwhal-microblog.php on line 265

Knowing that Posthaste was the underlying code, I suspect it’s an issue with php and the version in use. Apparently we’ve gotten to the version where posthasteForm is throwing the expected errors. 🙂

I’m not seeing any specific funcionality issues with the plugin, but it is throwing this error on the pages where Narwhal appears.