Before you release fry into a community they must be big enough to not fit into the mouth of any fish in the tank. They also must be strong enough and fast enough to swim for cover if one of the bigger fish gets a little aggressive. I usually wait until the fish are about 3/4 of an inch or 2 cm before adding them to a peaceful community and if there are any aggressive or large fish like angels or gouramis etc then i wait until they are over an inch. At 2 months i would expect that the fish are getting close to an inch in size but that depends are the size of tank they are growing in and what they are eating and how many times a day they are being fed... so just a guess. HTH
For me, my guppies are an inch by one month old. At 2months, it should be around 1.24 inches I'd say. Here's my guppy fry at 2-3 months old to give you a image:
My platies are a little under an inch and they are 2 months old. Just be sure that they are bigger than any of the fish's mouths if you want to release them.