Using the version -1 technique
(BeagleBoneBlack)ubuntu@localhost:~$ snappy list -v
Name Date Version Developer
ubuntu-core* 2015-04-10 119
ubuntu-core 2015-04-10 119
beagleboneblack* 2015-04-10 1.4 sergiusens
(BeagleBoneBlack)ubuntu@localhost:~$ snappy list --updates