When likely to get greencard and travel document for parents

[Ayish]

Dear all

My parents got i-485 reciept and i-131 reciept on 3/16/18 and did bimetric on 4/16/18.We could not see any updation of status online
When it is likely to get travel document and green card for them.Is there any condition in travel document that they have to return to USA within any stipulated time?

Request help on the same

Thanks and regards
Ganesan