PHP Warnings in server log file

Getting the following entries in an PHP error log on our host’s server. Have to delete the file regularly as it gets too large!!

[07-Sep-2020 11:45:16 UTC] PHP Warning: Illegal string offset ‘header-title’ in /home/dibdench/public_html/wp-content/plugins/wptouch/core/class-wptouch-pro.php on line 580
[07-Sep-2020 11:45:16 UTC] PHP Warning: Illegal string offset ‘link-color’ in /home/dibdench/public_html/wp-content/plugins/wptouch/core/class-wptouch-pro.php on line 647
[07-Sep-2020 11:45:16 UTC] PHP Warning: Illegal string offset ‘link-color’ in /home/dibdench/public_html/wp-content/plugins/wptouch/core/class-wptouch-pro.php on line 648
[07-Sep-2020 11:45:16 UTC] PHP Warning: Illegal string offset ‘header-background-color’ in /home/dibdench/public_html/wp-content/plugins/wptouch/core/class-wptouch-pro.php on line 651
[07-Sep-2020 11:45:16 UTC] PHP Warning: Illegal string offset ‘header-background-color’ in /home/dibdench/public_html/wp-content/plugins/wptouch/core/class-wptouch-pro.php on line 652
[07-Sep-2020 11:45:16 UTC] PHP Warning: Illegal string offset ‘header-border-color’ in /home/dibdench/public_html/wp-content/plugins/wptouch/core/class-wptouch-pro.php on line 655
[07-Sep-2020 11:45:16 UTC] PHP Warning: Illegal string offset ‘header-border-color’ in /home/dibdench/public_html/wp-content/plugins/wptouch/core/class-wptouch-pro.php on line 656
[07-Sep-2020 11:45:16 UTC] PHP Warning: Illegal string offset ‘header-title’ in /home/dibdench/public_html/wp-content/plugins/wptouch/core/class-wptouch-pro.php on line 580
[07-Sep-2020 11:47:32 UTC] PHP Warning: ini_set() has been disabled for security reasons in /home/dibdench/public_html/wp-content/plugins/download-manager/download-manager.php on line 73