JavaScript SDK - Prefix list version required to modify entry despite not being a required parameter

According to the JavaScript aws-sdk documentation, the version number of a managed prefix list is not a required parameter when modifying an entry.

However, when I attempt to do so, I hit a MissingParameter: A prefix list version is required error.

If I set the CurrentVersion parameter to the version of the prefix list, I am able to update the entry. However, this information is not provided when calling describeManagedPrefixLists so I have to manually locate the version number in the console and update my code for it to work.

Is there a way to locate the current version number programmatically, or get past the prefix list version being a required field?

const modifyEntryParams = {
  PrefixListId: currentPrefixListID,
  CurrentVersion: 289,
  AddEntries: [{
    Cidr: currentIP,
    Description: name
  }]
}
ec2.modifyManagedPrefixList(modifyEntryParams, function(err, data) {
  if (err) console.log(err, err.stack);
  else     console.log("modify success",data);
});