Have just upgraded to WP 5.5 and now have PHP deprecated notices in my debug.log file:-
Are either of these relevant to Toolset plugins?
[12-Aug-2020 06:11:12 UTC] PHP Deprecated: wp_make_content_images_responsive is <strong>deprecated</strong> since version 5.5.0! Use wp_filter_content_tags() instead. in /home/XXXXX/public_html/wp-includes/functions.php on line 4773
[12-Aug-2020 06:11:12 UTC] PHP Deprecated: class-phpmailer.php is <strong>deprecated</strong> since version 5.5.0! Use wp-includes/PHPMailer/PHPMailer.php instead. The PHPMailer class has been moved to wp-includes/PHPMailer subdirectory and now uses the PHPMailer\PHPMailer namespace. in /home/XXXXX/public_html/wp-includes/functions.php on line 4963
[12-Aug-2020 06:11:12 UTC] PHP Deprecated: class-smtp.php is <strong>deprecated</strong> since version 5.5.0! Use wp-includes/PHPMailer/SMTP.php instead. The SMTP class has been moved to the wp-includes/PHPMailer subdirectory and now uses the PHPMailer\PHPMailer namespace. in /home/XXXXXXX/public_html/wp-includes/functions.php on line 4963
I have one of these errors since I updated, it pops up every time I submit a Toolset form:
Deprecated: wp_make_content_images_responsive is deprecated since version 5.5.0! Use wp_filter_content_tags() instead. in /home/c/.../.../public_html/wp-includes/functions.php on line 4773
However, the notices you reported were not triggered on our tests, maybe they are not caused by Toolset. To confirm that, deactivate Toolset plugins for a while and check if the notices are still logged, if they are not, we can take a copy of your website and analyze it.