Hardware Acceleration Required
Updating the software won't help. Decoding H.264 in software for even Full HD content, much less 4K, will be beyond the ability of any Android CPU. Going up to H.265 (HEVC) will be worse. Unless the graphics chip can provide hardware acceleration for a new codec (not going to happen) then you can forget decoding on that system. The sad reality is that forwards compatibility isn't worth attempting.
The move to increase the bit-depth (per channel) to 10 in the 4K H.265 standard is another example of why forwards compatibility won't work. Even if the processing unit could decode the video, there would be no way to display the 10-bit colour-depth on an old 8-bit display.