Website broke down after update

Hi, I always was very happy with Polylang, but today hell broke out.
The website is showing a list of fatal errors after the last update, and even the stored old version won’t work anymore. Here is the list of error messages I’m getting:

Notice: Trying to get property of non-object in (…)/wp-content/plugins/polylang/include/plugins-compat.php on line 89

Warning: array_merge() [function.array-merge]: Argument #1 is not an array in (…)/wp-content/plugins/polylang/include/plugins-compat.php on line 89

Warning: array_merge() [function.array-merge]: Argument #1 is not an array in (…)/wp-content/plugins/polylang/include/plugins-compat.php on line 89

Warning: array_merge() [function.array-merge]: Argument #1 is not an array in (…)/wp-content/plugins/polylang/include/plugins-compat.php on line 89

Warning: array_merge() [function.array-merge]: Argument #1 is not an array in (…)/wp-content/plugins/polylang/include/plugins-compat.php on line 89

Warning: array_merge() [function.array-merge]: Argument #1 is not an array in (…)/wp-content/plugins/polylang/include/plugins-compat.php on line 89

Warning: array_merge() [function.array-merge]: Argument #1 is not an array in (…)/wp-content/plugins/polylang/include/plugins-compat.php on line 89

Warning: array_merge() [function.array-merge]: Argument #1 is not an array in (…)/wp-content/plugins/polylang/include/plugins-compat.php on line 89

Warning: Cannot modify header information – headers already sent by (output started at (…)/wp-content/plugins/polylang/include/plugins-compat.php:89) in (…)/wp-includes/pluggable.php on line 1178

Please help! Fast?
Thank you so much.
Ellen

https://wordpress.org/plugins/polylang/