How to install SUPEE-8788
October 12, 2016: Community Edition 1.9.3 and SUPEE-8788 Provide Critical Security & Functional Updates – 10/12/2016 Community Edition 1.9.3 and SUPEE-8788 resolve multiple security issues, including critical vulnerabilities with certain payment methods and Zend Framework libraries. Community Edition 1.9.3 also includes over 120 product quality enhancements and support for PHP 5.6.
New SUPEE-8788v2 patch can be downloaded as usual from Downloads page: https://www.magentocommerce.com/products/downloads/magento/ or installed as a regular Magento upgrade via Downloader (it is included in Magento 1.9.3 version).
Step 0: Preparations
Note: Make sure to Disable Magento Compiler at System > Configuration > Tools > Magento Compiler and clear compiled cache.
Step 1: Verify your Magento version
As you can see in the example, it is Magento 1.9.2.4
Step 2: Download corresponding patches
Patches are obtained from https://www.magentocommerce.com/products/downloads/magento/
Make sure to get the right version.
Step 3: Place patches into Magento Root directory
Upload your files into Magento root directory. It is important to place patch files directly into Magento root directory and execute it also directly in Magento root directory.
Step 4: Run the patches
Step 5: Verification and flush of PHP opcode cache
Test that your store is working. If you use PHP opcode caches (OPCache/APC/XCache/eAccelerator) make sure to flush it after patching (or restart webserver), otherwise code will continue to run from caches.
Additionally, if your store still use default /admin/ path, you may consider securing your Magento /admin/ by admin path changeand restrict access to /downloader/
Known issues
The issue is caused by conflict with changes from SUPEE-1533. You need to revert SUPEE-1533 patch. Please make sure also that you are installing SUPEE-8788v2 version re-uploaded by Magento on October 15.
If you have any difficulties with applying the patches please let us know in. Contact us, so we can find the solution together.