Error message after update

Hello all,

I received the following message several times because of an unsuccesful plugin update from version 3.2.14 to version 3.3.0.
The update is marked as ‘unavailable’ and it prevented me from logging into word press various times.

The support team of my domain provider had to be changed the PHP to a backup version in order to allow me in.
But even after I tried again the update and it does not work on the earlier version of wordpress.

Warning: Declaration of Axiom_Plugin_Updater::download_package($package, $check_signatures = false) should be compatible with WP_Upgrader::download_package($package, $check_signatures = false, $hook_extra = Array) in /home/customer/www/lisangavibes.com/public_html/wp-content/plugins/masterslider/admin/includes/classes/class-axiom-plugin-updater.php on line 29

Warning: Cannot modify header information – headers already sent by (output started at /home/customer/www/lisangavibes.com/public_html/wp-content/plugins/masterslider/admin/includes/classes/class-axiom-plugin-updater.php:29) in /home/customer/www/lisangavibes.com/public_html/wp-includes/pluggable.php on line 1296

Thank you for your help