The problem that this fix addresses is internal handling of a SMS message that contains extended characters; without the patch what happens is the device trashes your incoming SMS without a trace, after the device has niformed the network that the message has been delivered successifully.

This is extremely bad as it leads to situation where the sender thinks that the receiver has seen the message and the receiver has no idea that a message ever even arrived

To be able to send emoji in SMS, you need this.