ACCA/ Johnson
Neither the Supreme Court holding that the residual clause of the ACCA was impermissibly vague nor the Supreme Court holding that a certain state offense was not a valid predicate (nor the two combined) were changes in the substantive law to be made retroactively applicable to cases on collateral review.
http://media.ca11.uscourts.gov/opinions/pub/files/201515493.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.