Simply works for me for a a while now

However, it looks like it could use a bit of update ??
Following is what I see upon clicking “Activate” this plugin in WordPress backend:

Notice: Undefined index: cache_view_type in /var/www/html/tap/dev/forums/wp-content/plugins/post-views/post-views.php on line 118 Notice: Undefined index: cache_output_type in /var/www/html/tap/dev/forums/wp-content/plugins/post-views/post-views.php on line 122 Notice: Undefined index: cache_post_id in /var/www/html/tap/dev/forums/wp-content/plugins/post-views/post-views.php on line 126 Notice: Undefined index: cache_time_span in /var/www/html/tap/dev/forums/wp-content/plugins/post-views/post-views.php on line 127 Notice: Use of undefined constant is_robot – assumed ‘is_robot’ in /var/www/html/tap/dev/forums/wp-content/plugins/post-views/post-views.php on line 588 Notice: has_cap was called with an argument that is deprecated since version 2.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/html/tap/dev/forums/wp-includes/functions.php on line 2722 Notice: has_cap was called with an argument that is deprecated since version 2.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/html/tap/dev/forums/wp-includes/functions.php on line 2722 Notice: add_contextual_help is deprecated since version 3.3! Use get_current_screen()->add_help_tab() instead. in /var/www/html/tap/dev/forums/wp-includes/functions.php on line 2638