Shares in AIM-listed Escher Group plunged on Monday morning after the group warned the roll-out of its software by a particular customer was progressing more slowly than originally anticipated.As a result the majority of its licensing revenue will now be recognised in the second half.The group will recognise just $1.8m of the outstanding $6m licensing revenue in the first half of 2014. Escher stressed that its outlook for the full-year was unchanged. The customer was continuing to roll-out the software to its Post Office network, and Escher "remains confident" that the customer will have deployed the software to a sufficient number of workstations to trigger the full license payment in the second half.Chief Executive Officer, Liam Church, added: "Our software is currently live in a number of the customer's post offices and the roll-out is expanding on a weekly basis. We continue to support the customer in a large and complex software deployment exercise."The share price had slumped 19.08% to 265p by 08:14.NR