While we intend to update IC2 to newer versions, it's a very time-consuming process. I'd assume that it'd take about 4 months to update to 1.13/1.14 if we put all of our spare time into updating IC2. However since we have other things to do as well and it's quite easy to lose motivation to continue minecraft modding when updating mods for a while, I don't think it'll happen anytime soon.
It's clear the community wants to have IC2 for newer MC versions, but it requires more work than many of you would think. IC2 for newer MC versions will come when/if we are ready for it.
That being said, if someone wants to help in the IC2 development/updating process, we're always open for having a few extra hands, so if you think you can help, please let us know.