The 200_jsonprotocol.t test may fail, probably because order of hashes is random in newer perls:
# Failed test 'JSONProtocol generated the expected output'
# at t/200_jsonprotocol.t line 45.
# got: '[1,"add",1,1,{"2":{"i32":32},"1":{"i32":15}}]'
# expected: '[1,"add",1,1,{"1":{"i32":15},"2":{"i32":32}}]'
# Looks like you failed 1 test of 1.
t/200_jsonprotocol.t .......