Upgrade to v3.1.15 causes curious php7.0 and php7.3 mix

I've just upgraded to v3.1.15. Everything "appears" to have gone well, sites and interface still work etc. One thing I noticed was in

Code:

nginx/sites-available/apps.vhost

where the upgrade appears to have mixed php versions 7.0 and 7.3 and also the sock paths are different. There are 2 things to note here:

1. Why does one path use
   Code:

   /var/lib/

   ... and the other path use
   Code:

   /var/run/

   ...?
2. Why does one path go from
   Code:

   7.0

   to
   Code:

   7.3

   and the other stay on
   Code:

   7.0

   ...?

Confused? So am I Here's the diff to make things clearer:

Code:

@@ -44,7 +52,7 @@ server {
 
                # PHP only, required if PHP was built with --enable-force-cgi-redirect
                fastcgi_param   REDIRECT_STATUS         200;
-               fastcgi_pass unix:/var/lib/php7.0-fpm/apps.sock;
+               fastcgi_pass unix:/var/lib/php7.3-fpm/apps.sock;
                fastcgi_index index.php;
                fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
                #fastcgi_param PATH_INFO $fastcgi_script_name;
@@ -91,7 +99,7 @@ server {
                        fastcgi_param   REDIRECT_STATUS         200;
                        # To access phpMyAdmin, the default user (like www-data on Debian/Ubuntu) must be used
                        #fastcgi_pass 127.0.0.1:9000;
-                       fastcgi_pass unix:/var/lib/php7.0-fpm/apps.sock;
+                       fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;
                        fastcgi_index index.php;
                        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
                        fastcgi_buffer_size 128k;
@@ -107,7 +115,7 @@ server {
         location /phpMyAdmin {
                rewrite ^/* /phpmyadmin last;
         }
-
+
         location /squirrelmail {
                root /usr/share/;
                index index.php index.html index.htm;
@@ -141,7 +149,7 @@ server {
                        fastcgi_param   REDIRECT_STATUS         200;
                        # To access SquirrelMail, the default user (like www-data on Debian/Ubuntu) must be used
                        #fastcgi_pass 127.0.0.1:9000;
-                       fastcgi_pass unix:/var/lib/php7.0-fpm/apps.sock;
+                       fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;
                        fastcgi_index index.php;
                        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
                        fastcgi_buffer_size 128k;

Additional information is that, even if I have some old php7.0 lying around (and I'm actually trying to remove the cruft from previous OS versions so as to maintain a clean system), I'm actively using php7.3 on Debian Buster (10).

Code:

cat /etc/debian_version
10.1

Code:

php -v
PHP 7.3.9-1