Database
[{id:"6229d3fd40bac327243e4ww2",userID:"594e710c-c632-3ae-929a-f13e294ee6ef",appID:"622994e2b98225609b89affd",notifications:{6229d3e040bac3272qwe4441:1,622ew3e041bac3272qwe4441:1}}]
Query
db.collection.update({},[{$set:{notifications:{$arrayToObject:{$map:{input:{$objectToArray:"$notifications"},as:"n",in:{k:"$$n.k",v:{a:"$$n.v",b:false}}}}}}}],{multi:true})