trouble saving options (parameter must implement Countable, cannot modify header info)

[monadam]

When I try to save my options at wp-admin/options-general.php, I get the following errors:

Warning: count(): Parameter must be an array or an object that implements Countable in /app/public.built/wp-admin/includes/template.php on line 1447

Warning: Cannot modify header information - headers already sent by (output started at /app/public.built/wp-admin/includes/template.php:1447) in /app/public.built/wp-includes/pluggable.php on line 1210

Any idea how to fix this? Thanks

[monadam]

Also, sometimes all my pages and menus go missing, and I get the following error:

Warning: mysqli_set_charset(): Error executing query in /app/public.built/wp-includes/wp-db.php on line 823

I saw that someone had a similar problem and its solution was to edit wp-config.php with something like the following:

define( 'DB_CHARSET',           'utf8mb4'                         );
define( 'DB_COLLATE',           'utf8mb4_general_ci'              );

So I did that, reinstalled wordpress and everything, but still I get this error. I think it occurs when I use the site too much.

[monadam]

ah, the fix was very easy, this is what I did:

             "type": "package",
             "package": {
                 "name": "WordPress/WordPress",
-                "version": "4.8.3",
+                "version": "4.9.1",
                 "dist": {
                     "type": "zip",
-                    "url": "https://github.com/WordPress/WordPress/archive/4.8.3.zip"
+                    "url": "https://github.com/WordPress/WordPress/archive/4.9.1.zip"
                 }
             }
         },

problem solved. thanks for the amazing software.

edit: I should mention that after making these edits, I followed the instructions to update wordpress on the README.md.