1. A computer-implemented method comprising: receiving, by a directory server, a query for an attribute associated with a Lightweight Directory Access Protocol (LDAP) entry, wherein the attribute is stored in a repository and contains a plurality of pairs of values, with each pair containing an attribute value and a corresponding version number stored as a subtype of the attribute; determining, by the directory server, whether the query includes a version number of the attribute; in response to a determination that the query includes a version number, returning a first attribute value that corresponds to the version number in the query; in response to a determination that the query includes a predetermined symbol, returning all versions of the attribute; and in response to a determination that the query does not include a version number or the predetermined symbol, returning a second attribute value that corresponds to a current version of the attribute.