What is the difference between magento 1.9.2.4 and magento 1.9.3.0?

You can find the full list of differences in the official release notes: http://devdocs.magento.com/guides/m1x/ce19-ee114/ce1.9_release-notes.html#ce19-1930

Module fixing all the bugs

This module fixes the known bugs I'm trying to keep it up to date: https://github.com/digitalpianism/bugfixes

Side note

There used to be a bug in Magento where the passwords would not display in the new account email template. Most of the people (including me) assumed it was a security enhancement (see here: https://magento.stackexchange.com/a/46793/2380) but it was actually a bug which has been fixed in 1.9.3.0.

Known issues

As of now, there's several known bugs with 1.9.3.0:

• Fixed in 1.9.3.1 : Magento 1.9.3: every product is displayed in the search in full text mode (fixed in module above)
• Fixed in 1.9.3.1 : SOAP connection problems after 1.9.3.0 update (fixed in module above)
• Fixed in 1.9.3.1 : Send auto generated password does not work for some customers, fix here: https://gist.github.com/p3mbo/224f01996ff5b4849d189c38325c0bbd (fixed in module above)
• Fixed in 1.9.3.1 : Possible issue with bundle price as configured: Upgraded from 1.9.2.4 to 1.9.3 Bundle "Price as configured" Price Shows Zero (fixed in module above)
• Fixed in 1.9.3.1 : Dropdown attributes frontend label disappears under certain conditions: https://github.com/digitalpianism/bugfixes/pull/1 (fixed in module above)
• Fixed in 1.9.3.1 : Undefined index session_expire_timestamp: https://tomlankhorst.nl/fix-magento-undefined-index-session_expire_timestamp/ (fixed in module above)
• Fixed in 1.9.3.1 : Free shipping using sales rules now calculated from subtotal excluding tax, fix here: https://gist.github.com/andrew-smart/c7db5b04b24e77dd344919ce64ecf2f1 (fixed in module above)
• Fixed in 1.9.3.1 : Flow Password Cron Task does not work (fixed in module above)
• Fixed in 1.9.3.1 : Every page redirect to homepage when session cookie lifetime is set to 0 (fixed in module above)
• Backward incompatible change for modules using the old uploader block (also affects 8788): https://magento.stackexchange.com/a/142013/2380
• Fixed in 1.9.3.1 : Exception addCrumbs() method call (in case getStoreConfig(web/default/show_cms_breadcrumbs) ) is undefined
• Possible issues with configurable swatches and product tabs: Magento 1.9.3 upgrade other problems encountered and Configurable Swatches not working after 1.9.3 Upgrade
• Image uploader not working anymore: Image uploader not working after Magento 1.9.3 upgrade / After Upgrading to 1.9.3 I can't insert a product image
• Images missing from the backend but present on front end: Image problem in the Admin after 1.9.3 upgrade / After upgrading to 1.9.3 - none of my product images are showing in the backend
• Fixed in 1.9.3.1 : Cannot upload more than 7 images via CSV import: When import Configurable product csv only 7 image upload in magento1.9.2.3?
• Default serialized configuration values do not work anymore: Default configuration value for serialized_array settings is ignored
• Not a 1.9.3 bug actually (see here: Catalog Price Rules Contains Condition) With flat catalog enabled, catalog rule condition such as "sku" contains "foo" don't work anymore

Also please note that the JS that handles the product options price has been moved from /js/varien/product.js to /js/varien/product_options.js so don't forget to add that file to your theme if you're facing the following issue: https://magento.stackexchange.com/a/141375/2380

PHP 7

For those using PHP 7 and the Inchoo module, Inchoo has released a new version of the module (2.0.0) which is only compatible with 1.9.3 don't forget to update: https://github.com/Inchoo/Inchoo_PHP7

There are two backward-incompatible changes in Magento 1.9.3:

1. Mage_Adminhtml_Block_Cms_Wysiwyg_Images_Content_Uploader parent class is removed.
2. Mage_Uploader_Model_Config_Abstract overrides the magic method __call and its behavior can be inconsistent.

Please check if any extensions/customisations are using/extending these functions/classes.

Also make sure after upgrading to Magento 1.9.3 to remove the following files to avoid security issues:

1. skin/adminhtml/default/default/media/flex.swf
2. skin/adminhtml/default/default/media/uploader.swf
3. skin/adminhtml/default/default/media/uploaderSingle.swf

For more information, refer to the release notes.

I am not a big fan of patching. Personally I remove all Magento files from their directories then upload the new version (using a shell script). All the files installed over the years like modules or themes are still there. For database I make a comparison between fresh installed versions. One way is creating or removing the columns/tables into the database, the other way is installing again Magento just changing /app/etc/local.xml file name. I prefer the first one.

If you do not change the database structure to version 1.9.3.0 you will get some errors or you cannot load admin area. If anyone is interested in some comparisons for Magento directories and databases between Magento CE 1.9.2.4 and 1.9.3.0 just download the file from here:

Magento Comparison: versions 1.9.2.4 - 1.9.3.0

There are two html files with very nice visual results.

I updated 4 stores today using my method instead of patching. All are running without any issues.