Errors on Activation

I have just loaded version 2.4.4 of Sendit Newsletter and got a flood of errors when I activated it – is this to be expected?

I am using PHP version 5.6.27

The errors are

Notice: Constant SENDIT_EMAIL_TABLE already defined in /var/www/clients/client16/web72/web/wp-content/plugins/sendit/libs/constants.php on line 4

Notice: Constant SENDIT_LIST_TABLE already defined in /var/www/clients/client16/web72/web/wp-content/plugins/sendit/libs/constants.php on line 5

Notice: Constant SENDIT_VERSION already defined in /var/www/clients/client16/web72/web/wp-content/plugins/sendit/libs/constants.php on line 6

Notice: Constant SENDIT_DB_VERSION already defined in /var/www/clients/client16/web72/web/wp-content/plugins/sendit/libs/constants.php on line 7

Notice: register_sidebar_widget is deprecated since version 2.8.0! Use wp_register_sidebar_widget() instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 3828

Notice: register_widget_control is deprecated since version 2.8.0! Use wp_register_widget_control() instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 3828

Notice: Undefined index: post in /var/www/clients/client16/web72/web/wp-content/plugins/sendit/libs/admin/meta-boxes.php on line 11

Notice: Undefined variable: themename in /var/www/clients/client16/web72/web/wp-content/plugins/sendit/libs/admin/admin-core.php on line 817

Notice: Undefined variable: shortname in /var/www/clients/client16/web72/web/wp-content/plugins/sendit/libs/admin/admin-core.php on line 972

Notice: Undefined index: page in /var/www/clients/client16/web72/web/wp-content/plugins/sendit/libs/admin/admin-core.php on line 992

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: has_cap was called with an argument that is deprecated since version 2.0.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /var/www/clients/client16/web72/web/wp-includes/functions.php on line 4020

Notice: Trying to get property of non-object in /var/www/clients/client16/web72/web/wp-content/plugins/sendit/libs/extensions-handler.php on line 56