Packet Tracer version 5.3.3 is a maintenance release that fixes functional and technical issues in the previous versions. It replaces Packet Tracer version 5.3.2.
Packet Tracer 5.3.3 supports activities authored in Packet Tracer 4.x, 5.0.x, 5.1.x, 5.2.x, and 5.3.x. Please note that the last two courses of the CCNA Discovery and CCNA Exploration curricula require Packet Tracer version 4.11 at a minimum, CCNA Security requires version 5.2 at a minimum, and the Packet Tracer Skills Based Assessments require version 5.3.2 at a minimum. The curricula are fully compatible with Packet Tracer 5.3.3.
You can download both the Packet Tracer application and tutorial files in one download package. However, due to the large file size it is faster to download the application by itself, if that is all you need. Choose the download option appropriate for your needs.