5.1.0
To upgrade from 5.0.x to 5.1.0 please replace the following files with the ones from the latest package:

/index.php
/application/core/CT_Model.php
/application/controllers/Admin.php
/application/helpers/coin_table_helper.php
/application/libraries/Coin_table.php
/application/models/Options_model.php
/application/views/admin/base.php
/application/views/frontend/pages/exchanges.php

5.1.1
To upgrade from 5.1.0 to 5.1.1 please replace the following files with the ones from the latest package:

/index.php
/application/controllers/Api.php

5.1.2
To upgrade from 5.1.1 to 5.1.2 please replace the following files with the ones from the latest package:

/index.php
/application/controllers/Api.php
/application/libraries/Coin_table.php

5.2.0
To upgrade from 5.1.2 to 5.2.0 please replace the following files with the ones from the latest package:

/index.php
/application/config/coin_table.php
/application/controllers/Admin.php
/application/controllers/Api.php
/application/controllers/Frontend.php
/application/controllers/Upgrade.php
/application/core/CT_Controller.php
/application/languages/(*)/coin_table_lang.php
/application/libraries/Coin_table.php
/application/models/Coins_model.php
/application/models/Options_model.php
/application/views/admin/template/currency_page.php
/application/views/frontend/page/currency.php
/assets/admin/js/admin.js
/assets/admin/js/admin.min.js
/assets/frontend/css/frontend.css
/assets/frontend/js/market.js
/assets/frontend/js/market.min.js
/assets/frontend/js/currency.js
/assets/frontend/js/currency.min.js

5.2.1
To upgrade from 5.2.0 to 5.2.1 please replace the following files with the ones from the latest package:

/index.php
/application/controllers/Api.php
/application/libraries/Coin_table.php
/application/models/Coins_model.php

5.3.0
To upgrade from 5.2.1 to 5.3.0 please replace the following files with the ones from the latest package:

/index.php
/application/controllers/Api.php
/application/controllers/Frontend.php
/application/controllers/Upgrade.php
/application/core/CT_Model.php
/application/libraries/Coin_table.php
/application/models/Coins_model.php
/application/models/Options_model.php
/assets/frontend/js/currency.js
/assets/frontend/js/currency.min.js
/assets/frontend/js/market.js
/assets/frontend/js/market.min.js

Errors Hidden
Error’s messages are disabled in production environment. Check the error log file instead or enable error reporting by changing the ENVIRONMENT constant in index.php file:

define('ENVIRONMENT', 'development');

HTTPS
The use of SSL is essential for secure browsing, so you should only choose web hostings that provide certificates. Use “https://” instead of “http://” in the base_url (config/config.php)

$config['base_url'] = 'https://example.domain/';

Also add this rewrite rule to the beginning of the root .htaccess (Apache or Litespeed):

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [R,L]
</IfModule>

Make sure that you uploaded the .htaccess file to the root directory and application/controller/Install.php. After the installation, the application/controller/Install.php file will be deleted (if possible) to avoid resets on database.

If you are using 1and1 hosting, you must change the root .htaccess file at the bottom:

<IfModule mod_rewrite.c>
RewriteBase /
RewriteEngine on
RewriteCond $1 !^(index\.php|assets|images|coins_images)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?/$1 [L,QSA]
</IfModule>

Could also happen with other web hosting providers.