MongoDB Ops Manager Basic Installation and Configuration

This is what we are looking to update

db.getCollection('location').find({"correlationId.correlation":"MN09"})
Result:
{
"_id" : ObjectId("4523452345235234"),
"correlationId" : {
"correlation" : "MN09"
},
"sortSequence" : 120,
"code" : "MN09",
"description" : "Manhattan 9",
"legacyZone" : "West",
"locationTypeId" : {
"correlation" : "DISTRICT"
},
"garageCode" : "MW09G",
"servicesSelf" : true,
"servicedBy" : [
{
"correlation" : "MN12"
}
],
"workUnit" : {
"correlation" : "MNBO"
}
}

we would like to do a find and update on

"servicedBy" : [
{
"correlation" : "MN12"
}
]

using
db.getCollection('location').update(
{"correlationId.correlation":"MN09"},
{ $set : { "servicedBy.$[elem].correlation" : "MN04"}},
{ arrayFilters: [{ "elem.correlation" : {$eq: "MN12"} }], multi:true}
)

now we query again

db.getCollection('location').find({"correlationId.correlation":"MN09"})
Result:
{
"_id" : ObjectId("4523452345235234"),
"correlationId" : {
"correlation" : "MN09"
},
"sortSequence" : 120,
"code" : "MN09",
"description" : "Manhattan 9",
"legacyZone" : "West",
"locationTypeId" : {
"correlation" : "DISTRICT"
},
"garageCode" : "MW09G",
"servicesSelf" : true,
"servicedBy" : [
{
"correlation" : "MN04"
}
],
"workUnit" : {
"correlation" : "MNBO"
}
}

ref:

https://docs.mongodb.com/manual/reference/operator/update/positional-filtered/#up._S_[%3Cidentifier%3E]