I'm the developer who was commissioned to create the 0.18 client by Chekaz.
I've put my suggestions on the Telegram channel. We want a single chain after all the dust has settled, 0.17 has already broken consensus with 0.13, which is why you do not restore consensus breaking validation without doing so at a set height so everyone can upgrade in good time.
My suggestion is to update 0.17 to follow the 0.13 chain and release it after the validation restoration height in 0.18, then 0.17 and 0.18 will exist on the same chain and as long as the majority of miners are on 0.17 and 0.18 then 0.13 will follow it. The only concern is if someone tries to spend the 62B stolen coins, moving these funds on 0.18 is now blocked on a consensus level, 0.13 only protected the mempool which is why they moved and 0.17 has no protection against this at all. A new 0.17 version should also block spending of those stolen funds on a consensus level, I can send create the pull request on their 0.17 repo to add this feature.
I've also recommended to to Chekaz that historical validation be restored in the 0.18 release once validation has been restored, then 0.18 will be a fully validating release as it should be, this could not be done from the outset or consensus would break at some point as demonstrated by 0.17.
Side note, all this talk of a 51% attack is incorrect and there's a lot of other misinformation going round. This sort of thing is counterproductive, this is a purely technical issue that can be resolved by dialog.
Peter
Thank you.
I repeat again and again here, that in blockchain development previous works and level of knowledge matter.
It is necessary to listen to experts, and if you don't know ChekaZ, listen at least to Peter, Feathercoin founder. If you don't know, Feathercoin is one of the first altcoins, very famous one.
About 62B, if 0.17 removed protection, they removed not only protection for 62 B which did not work, but also the protection for 12B from Dec, 2014 thefts, and this protection worked, at least a hacker never moved these coins, and in 0.17 they are free and ready to be dumped. You can just make a research and find this and other information in transparent posts in this ANN thread and in the old ANN thread, created by original dev in 2013, or ask members who know or remember Mooncoin history.