A method of handling concurrent accesses at an entry in a user data repository, hereinafter UDR, wherein the entry in the UDR is concurrently accessed with Lightweight Directory Access Protocol, hereinafter LDAP, requests from one or more front-end servers equipped with respective LDAP-clients, the method comprising the steps of: - receiving (S-115, S-125), at the UDR from the one or more front-end servers, one or more LDAP search requests to read a set of user data for a user; - providing (S-120, S-135), from the UDR to the one or more front-end servers, the set of user data along with a current version value assigned (S-100) to the set of user data; - receiving, at each of the one or more front-end servers, the set of user data along with the current version value assigned by the UDR; - determining, by a front-end server amongst the one or more front-end servers, new data to replace in the set of user data and a new version value to be assigned to the set of user data; - submitting (S-145, S-165), from said front-end server to the UDR, an LDAP modify request which includes: a first replace indication with the new data to replace in the set of user data, a delete indication with the current version value received from the UDR, and a second replace indication with the new version value determined by said front-end server; - upon receiving the LDAP modify request (S-145, S-165) from said front-end, checking at the UDR (S-150, S-170) whether the current version value received from said front-end server with the delete indication matches the current version value assigned at the UDR to the set of user data; and - where there is a match: replacing (S-155) the current version value assigned at the UDR to the set of user data by the new version value received from said front-end server with the second replace indication, and replacing (S-160) corresponding data in the set of user data by the new data received with the first replace indication; or - where there is not a match: rejecting (S-175, S-240) the LDAP modify request. - receiving (S-115, S-125), at the UDR from the one or more front-end servers, one or more LDAP search requests to read a set of user data for a user; - providing (S-120, S-135), from the UDR to the one or more front-end servers, the set of user data along with a current version value assigned (S-100) to the set of user data; - receiving, at each of the one or more front-end servers, the set of user data along with the current version value assigned by the UDR; - determining, by a front-end server amongst the one or more front-end servers, new data to replace in the set of user data and a new version value to be assigned to the set of user data; - submitting (S-145, S-165), from said front-end server to the UDR, an LDAP modify request which includes: a first replace indication with the new data to replace in the set of user data, a delete indication with the current version value received from the UDR, and a second replace indication with the new version value determined by said front-end server; - upon receiving the LDAP modify request (S-145, S-165) from said front-end, checking at the UDR (S-150, S-170) whether the current version value received from said front-end server with the delete indication matches the current version value assigned at the UDR to the set of user data; and - where there is a match: replacing (S-155) the current version value assigned at the UDR to the set of user data by the new version value received from said front-end server with the second replace indication, and replacing (S-160) corresponding data in the set of user data by the new data received with the first replace indication; or - where there is not a match: rejecting (S-175, S-240) the LDAP modify request.