I've withdrawn the 0.16.3 release and deleted the repository as it's clear that supporting this particular upgrade is beyond my skillset.
I've done the protocol upgrade on another network from 0.8 through 0.14.3.
This should be something we can collaborate on to complete for Datacoin in time to bring 0.16.3 or whatever you like.
From what I remember, the last Bitcoin protocol upgrade was the August, 2017 upgrade which was brought in by 0.14.2 and then there was the lil fix to make 0.14.3.
It would make sense the can be no relay of TX between old 0.8 nodes and anything which requires BIP 66.
When I did it for the other network, I did it in 3 pieces to go from old protocol to current.
The first network upgrade was just another 0.8 branch release which fixed the difficulty adjustment algorithm.
Afterwards, a 0.13.0 release occurred to usher in BIP66/BIP65 by consensus.
Lastly, a 0.14.3 release was performed to complete the network upgrade.
Along the way, this included the support for BIP 32 as well as a SegWit.
I don't think we need to go the scenic route here but its certainly a possibility we can entertain as well.
Are you at all interested in a IsSuperMajority() network upgrade in a next release using this built-in pool code which could be patched into 0.13.0 (perhaps [or whatever you like]) and then once those are activated, [the IsSuperMajority() forks] continue to lock-in the version bits soft forks?
Since the pool side of the equation and solo mining side of the equation is looking to be more well managed right now, I wouldn't be opposed to doing a white-box generic unpolished but functionally precise wallet to usher in the IsSuperMajority() BIPs.
The hierarchical deterministic wallet comes with 0.13.0 iirc (BIP 32) and activating BIP 66 and BIP 65 with it (but especially BIP 66) will give the Datacoin network a great baseline to then move people out of the 0.8 branch and ensure the problems associated with rejected transactions due to strict DER signatures (to prevent unintentional forks) may be resolved before attempting a SegWit network upgrade.
Also, I will be AFK a ton for the rest of the weekend - but I wanted to just pop in and thank you for the attention you're giving as caretaker for Datacoin and to help with strategy for future protocol upgrades now that more of the mining technology has been wrangled.
Apologies for the delay in my responding to your kind words and positive suggestions.
It's difficult to express this without a sense of sounding whiny ... I have spent some time thinking about this in depth but I just can't convince myself that there is sufficient residual interest in the Datacoin chain to justify the amount of effort required for a migration. There isn't even enough interest to protect the chain against the current exploitation by just one individual of the emissions rate/difficulty modifier relationship.
Although I see myself as merely an occasional technical contributor, I can see why public perception may prefer a caretaker interpretation. However, even as an erstwhile curator, the main issue is that there's very little left to curate. The community seems to have evaporated leaving a few isolated individuals remaining. Communication ranges from terse to non-existent. Both the mining pool and exchange listing persist via the goodwill of the operators towards a 2013-vintage altcoin.
I have to confess that I'm struggling for an answer to the question - What's the point of continuing to support the remnants of a community that don't appear to want support?