diff --git a/debian/ngcp-rtpengine-kernel-dkms.prerm b/debian/ngcp-rtpengine-kernel-dkms.prerm
index c6df3c03c..0cf711ad8 100644
--- a/debian/ngcp-rtpengine-kernel-dkms.prerm
+++ b/debian/ngcp-rtpengine-kernel-dkms.prerm
@@ -5,8 +5,8 @@ set -e
 package=ngcp-rtpengine-kernel-dkms
 name=ngcp-rtpengine
 
-version=`dpkg-query -W -f='${Version}' "$package" \
-        |rev|cut -d- -f2-|rev|cut -d':' -f2|tr -d "\n"`
+version=$(dpkg-query -W -f="\${Version}" "$package" \
+        |rev|cut -d- -f2-|rev|cut -d':' -f2|tr -d "\n")
 
 if [ -x /usr/sbin/ngcp-virt-identify ]; then
 	if /usr/sbin/ngcp-virt-identify --type container; then