These aren't about the 2016 election in particular, but it would seem that there is strong evidence that the security practices in place by many US states are inadequate, and there is often no "paper trail" to verify that results were tallied accurately after the fact if a recount is needed.
Considering the poor security, if the 2016 election was targeted, it is likely that the attacker(s) succeeded.
I believe this is the most up-to-date publication on the subject: https://cse.sc.edu/~buell/Public_Data/2019_VotingMachines.pd...
I would also recommend the documentary "I Voted" (https://www.imdb.com/title/tt4081950/).
These aren't about the 2016 election in particular, but it would seem that there is strong evidence that the security practices in place by many US states are inadequate, and there is often no "paper trail" to verify that results were tallied accurately after the fact if a recount is needed.
Considering the poor security, if the 2016 election was targeted, it is likely that the attacker(s) succeeded.