Changed behavior of _.flatten function in lodash v3? -

this line of code has worked couple of months in production:

_.chain(data.groups).flatten('filters').pluck('name').value(); 

so have list of groups, each group has collection of filters , filters have name property. want flat list of names. 100% sure code worked intended, because has been in production months, in tool intensively used.

last week, noticed our lodash version kinda outdated, updated from:

"lodash": "~2.4.1", 

to:

"lodash": "~3.9.3", 

suddenly, line mentioned above returns undefined (discovered in production, unfortunately). bit shocked behavior of such method changes on versions. apparently, because signatue of flatten method changed. ok, new major version, still expect backwards compatibility ...

how can achieve want in version 3 of lodash?