Lidl's new app is Lidl Plus and to encourage downloads they are giving people €5 off (if they spend over €25).
To get the €5 off:
1) download the app
2) once you've registered Lidl send you a €5 off coupon that you store in the app
3) show the coupon at checkout to get €5 off
Download details are here: https://www.lidl.ie/information/lidl-app