SUPEE-10888, Magento Commerce 1.14.3.10 and Open Source 1.9.3.10 contain multiple security enhancements that help close cross-site scripting (XSS), cross-site request forgery (CSRF) and other vulnerabilities.

1) Install SUPEE-10888 without SSH

Install Magento SUPEE 10888 with PrePatched Files (without SSH method):

Download the zip file for your Magento Version for the patch installation. You can also download these magentocommerce.com After downloading the files, just upload it to your Magento root folder

2) Install Magento SUPEE 10888 using SSH:

Upload the patch into your Magento root directory and run the appropriate SSH command:

For .sh file extension:

 sh patch_file_name.sh  

Example:

 sh PATCH_SUPEE-10888_CE_v1.9.1.1_v1-2018-09-18-02-53-38.sh  

For .patch file extension:

 patch —p0 < patch_file_name.patch  

Upgrade/Updating Procedure of Magento 2 by following these simple steps:

Step 1: First of all, connect to your web server via SSH. Using putty or any SSH client.

Step 2: Once your SSH connection is established, you will need to navigate to your Magento 2 ROOT directory.

Step 3: Now follow the order and use the following commands:

 php bin/magento maintenance:enable  
 composer require magento/product-community-edition 2.2.5 --no-update  
 composer update  
  rm -rf pub/static/frontend/* pub/static/adminhtml/* var/cache var/composer_home var/generation var/page_cache var/view_preprocessed var/di   
  php bin/magento setup:static-content:deploy   
  php bin/magento cache:clean && php bin/magento cache:flush   

After the upgrade, check your Magento version with the following command:

 php bin/magento --version  

Complete Working.

Magento 1.x website on PHP7, you need to make some little tweaks in your some Magento 1.x files to make it work without any issues.

1.1 app/code/core/Mage/Core/Model/Layout.php:555

 $out .= $this->getBlock($callback[0])->$callback[1](); 

With

 $out .= $this->getBlock($callback[0])->{$callback[1]}(); 

 'cache' =>  
  array (  
   'frontend' =>  
   array (  
    'default' =>  
    array (  
     'backend' => 'Cm_Cache_Backend_Redis',  
     'backend_options' =>  
     array (  
      'server' => '127.0.0.1',  
      'port' => '6379',  
      'persistent' => '',  
      'database' => '0',  
      'password' => '',  
      'force_standalone' => '0',  
      'connect_retries' => '1',  
      'read_timeout' => '10',  
      'automatic_cleaning_factor' => '0',  
      'compress_data' => '1',  
      'compress_tags' => '1',  
      'compress_threshold' => '20480',  
      'compression_lib' => 'gzip',  
      'use_lua' => '0',  
     ),  
    ),  
    'page_cache' =>  
    array (  
     'backend' => 'Cm_Cache_Backend_Redis',  
     'backend_options' =>  
     array (  
      'server' => '127.0.0.1',  
      'port' => '6379',  
      'persistent' => '',  
      'database' => '1',  
      'password' => '',  
      'force_standalone' => '0',  
      'connect_retries' => '1',  
      'lifetimelimit' => '57600',  
      'compress_data' => '0',  
      'compress_tgs' => '1',  
      'compress_threshold' => '20480',  
      'compression_lib' => 'gzip'  
      'automatic_cleaning_factor' => '0',  
     ),  
    ),  
   ),  
  ),  

Installing:

https://github.com/fernandofauth/magento2_datetime

Simply paste the FernandoFauth folder on (magento root)/app/code

After installing the module upgrade your store.

bin/magento setup:upgrade

Check if your cache is clean.

If using production mode, you need recomplie the store code.

Follow this steps
bin/magento setup:upgrade

bin/magento indexer:reindex

bin/magento deploy:mode:set production -s

bin/magento setup:di:compile

bin/magento setup:static-content:deploy (lang_code) [ ex: bin/magento setup:static-content:deploy pt_BR]

Other thing you can do is check your folder permissions.

Try this in design/frontend/Vendor_Name/Theme_Name/Magento_Catalog/templates/product/list.phtml

 $regprice = $_product->getPrice();  
 $specialprice = $_product->getSpecialPrice();  
 $yousave = number_format((float)($regprice - $specialprice), 2, '.', '');  
 $yousavepct = number_format((float)(100*(($regprice - $specialprice)/$regprice)), 0);  
 if($yousave > 0): ?>  
   <p class="you-save-statement">You save: $<?php echo $yousave; ?> (<?php echo $yousavepct; ?>%)</p>  
 <?php endif; ?>  

Notice: Undefined index: title in /vendor/magento/module-integration/Helper/Data.php on line 24

- I have read few articles and came to know that it is due to missing title in any of the modules acl.xml

- Go to your freshly created modules (some modules which you created last or before), open app/code/Name_Space/Module_Name/etc/acl.xml

 <?xml version="1.0" ?>  
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Acl/etc/acl.xsd">  
 <acl>  
   <resources>  
     <resource id="Magento_Backend::admin">  
       <resource id="Magento_Backend::stores">  
         <resource id="Magento_Backend::stores_settings">  
           <resource id="Magento_Config::config">  
             <resource id="Namespace_Modulename::config_namespace_modulename" title="Put Here the Title"/>  
           </resource>  
         </resource>  
       </resource>  
     </resource>  
   </resources>  
 </acl>  
 </config>