Looking at the user distribution chart, who are using Tizen 2.3 is still huge.
The reasons are as follows.
1. Unless they connect to WiFi they are never asked for the OS upgrade.
2. There is no incentive or push from Samsung to make them upgrade for the Tizen 2.4.
But, the problem for the developer is multifold.
1. Many Developer Tools have stopped support for the Tizen 2.3. For example, Unity 5.5 supports only Tizen 2.4 and above.
2. Developer cannot use the latest features provided by Tizen 2.4+ to retain support for 2.3, though Tizen 2.3 is used by only one device.
3. Cost of development increases as we have to concentrate to multiple OSes.
4. Cost and Time of Testing increases as we have to test on multiple OSes.
It is bad for Samsung too, as customers will not have positive image of the Tizen, as they are not using the latest OS version.
So, a major upgrade to Tizen 2.4 campaign for all the customers who visit Tizen App Store should comeup and they should be informed about what they are losing, if they do not upgrade. Even download using the Mobile Data should be pushed.