2020-10-21 phpmyadmin missing extensions

In this case is mbstring

let's check PHP Modules in my system (I use PHP 7.4)

$ php -m | grep -i mbstring
mbstring

it's should not miss! because the modules have installed. So, main problem is phpmyadmin (what I installed) cannot read modules in php7.4 or support PHP Version 7.4

Problem: something when wrong withbuild phpmyadmin

Solution: Installing phpmyadmin from source

this is how-to Installing phpmyadmin from source.

wget https://github.com/phpmyadmin/phpmyadmin/archive/RELEASE_5_0_4.tar.gz
tar -zxvf phpmyadmin-RELEASE_5_0_4.tar.gz
mv phpmyadmin-RELEASE_5_0_4 phpmyadmin
sudo cp -r phpmyadmin /usr/share

change permission

sudo chown -R www-data:www-data /usr/share/phpmyadmin
sudo chmod -R 755 /usr/share/phpmyadmin

and we will linked phpmyadmin with apache2

sudo vim /etc/apache2/conf-available/phpmyadmin.conf

<Directory "/usr/share/phpmyadmin>
  Order Deny,Allow
  Deny from all
  Allow from localhost
  Allow from 127.0.0.1
  Allow from 192.168.0.0/24
</Directory>

Alias /phpmyadmin /usr/share/phpmyadmin
Alias /phpMyAdmin /usr/share/phpmyadmin

Solution 2: installing phpmyadmin with fresh php7.4 installation

Delete all version of php in my machine may get default config, so this is best way to avoid miss php configuration or conflict modules in the past

sudo apt-get purge php7.*
sudo add-apt-repository ppa:ondrej/php
sudo apt -y install php7.4
sudo apt install phpmyadmin

install phpmyadmin with this ppa will bring all required modules or packages in spesific php version (php7.4), you don't need install anything else.

I hope this helps.