HDMI 1.3 vs 1.4
In May of 2009, version 1.4 of the HDMI specification was released, updating the capabilities of the standard as well adding new features that make it a bit more competitive with the emerging standards like DisplayPort. The most significant change that we get with version 1.4 is the increase of single link resolution from 2560×1600 to 4096×2160. Although this resolutions are far beyond what you can expect from an HDTV, they are still well within what you would expect from computer monitors, especially large ones, where HDMI is facing stiff competition from DisplayPort.
On the TV side, HDMI improves the support for 3D, which is becoming very popular due to some giant 3D animated movies. HDMI 1.4 supports 3D in all resolutions and even added standards on how the information would be sent across the interface. HDMI 1.3 did allow some sort of 3D but only for the 1080i resolution.
Aside from the improvements mentioned above, two new features were also added in version 1.4, the audio return channel and the Ethernet channel. The audio return channel is used to allow audio to travel both ways. This was created to eliminate the need to add another audio connection between a TV and player to allow the sound from the TV to be heard from the better speakers of the player. The Ethernet channel allows HDMI enabled devices to form a mini network so that they can route information. Instead of having an Ethernet connection for each of your device that are already connected via HDMI, you can simply use one connection on one device and have the information travel across the HDMI cable, thereby reducing the number of cables that are needed.
All of the features of HDMI 1.4 can be used while using older cables that were designed for version 1.3. That is except the Ethernet channel. For that you need a cable that was built for version 1.4. HDMI 1.4 also saw the introduction of the micro HDMI connector. It is identical to the bigger connectors and is pretty much like the micro USB connectors.
Summary:
1. HDMI 1.4 has a much higher resolution compared to 1.3
2. HDMI 1.4 totally supports 3D while 1.3 only supports 3D in 1080i
3. HDMI 1.4 is equipped with an audio return channel not present in HDMI 1.3
4. HDMI 1.4 has an Ethernet channel while 1.3 does not
5. HDMI 1.4 defines a newer cable standard than in 1.3