Apple Stringsdict format is used for storing plural keys and their values. The .stringsdict file is a .plist file that consists of key-value pairs.

Due to the specifics of .stringsdict, each plural key in iOS should be maintained as (at least) two keys in Lokalise. The first Lokalise key (for example number_of_days), which in fact is not plural, should contain the value of NSStringLocalizedFormatKey (for example %#@the_plural_1@).  The second Lokalise key (containing actual plurals) should be called the same as the first Lokalise key following :: and a reference used in the NSStringLocalizedFormatKey (for example number_of_days::the_plural_1). 

There is no limit on the number of references within each NSStringLocalizedFormatKey. Note, you need to export Apple Strings in order to get both .strings and .stringsdict in the bundle.