Thanks pronet you should fix the script. the VERSION should be __VERSION__. rest is fine and worked thanks.

Here is 9.0.0.0 that will compile with the latest kernel.

pkgbase=rtpengine
pkgname=('rtpengine' 'rtpengine-dkms')
pkgver=9.0.0.0
pkgrel=0
pkgdesc="The Sipwise media proxy for Kamailio"
url="https://github.com/sipwise/rtpengine"
license=('GPL3')
arch=('x86_64' 'i686' 'aarch64' 'armv7h')
depends=('libpcap' 'ffmpeg' 'hiredis' 'json-glib' 'libevent' 'libmariadbclient' 'openssl' 'pcre' 'xmlrpc-c' 'zlib')
optdepends=('libiptcdata' 'bcg729')
makedepends=('gperf' 'glib2' 'pkgconf')
source=("git+https://github.com/sipwise/rtpengine.git")
sha256sums=('SKIP')
prepare() {
  mv "${srcdir}/$pkgbase" "${srcdir}/${pkgname}-mr${pkgver}"
  cd "${srcdir}/${pkgname}-mr${pkgver}"
}
build() {
  cd "${srcdir}/${pkgname}-mr${pkgver}"
  make all
}
package_rtpengine() {
  cd "${srcdir}/${pkgname}-mr${pkgver}"
  install -Dm755 daemon/rtpengine $pkgdir/usr/bin/rtpengine
  install -Dm755 recording-daemon/rtpengine-recording $pkgdir/usr/bin/rtpengine-recording
  install -Dm755 iptables-extension/libxt_RTPENGINE.so $pkgdir/usr/lib/iptables/libxt_RTPENGINE.so
}
package_rtpengine-dkms() {
  depends=('linux-headers' 'dkms')
  cd "${srcdir}/$pkgbase-mr${pkgver}"
  # Copy dkms .conf
  install -Dm644 debian/dkms.conf.in "${pkgdir}/usr/src/${pkgbase}-${pkgver}/dkms.conf"
  cp -r kernel-module/* $pkgdir/usr/src/$pkgbase-$pkgver/
# Set name and version
  sed -e "s/VERSION/${pkgver}/" \
    -e "s/ngcp-rtpengine/rtpengine/" \
    -i "${pkgdir}/usr/src/${pkgbase}-${pkgver}/dkms.conf"
}

Here is updated PKGBUILD:

# Maintainer: robertfoster
pkgbase=rtpengine
pkgname=('rtpengine' 'rtpengine-dkms')
pkgver=7.1.1.1
pkgrel=1
pkgdesc="The Sipwise media proxy for Kamailio"
url="https://github.com/sipwise/rtpengine"
license=('GPL3')
arch=('x86_64' 'i686' 'aarch64' 'armv7h')
depends=('libpcap' 'ffmpeg' 'hiredis' 'json-glib' 'libevent' 'libmariadbclient' 'openssl' 'pcre' 'xmlrpc-c' 'zlib')
optdepends=('libiptcdata' 'bcg729')
makedepends=('gperf' 'glib2' 'pkgconf')
source=("https://github.com/sipwise/rtpengine/archive/mr$pkgver.tar.gz")
sha256sums=('5303e4b314988b41c4d81cac68af65552a41d75293d19442e3cb1a3acd62921d')

prepare() {
  cd "${srcdir}/${pkgname}-mr${pkgver}"
}

build() {
  cd "${srcdir}/${pkgname}-mr${pkgver}"
  make all
}

package_rtpengine() {
  cd "${srcdir}/${pkgname}-mr${pkgver}"
  install -Dm755 daemon/rtpengine $pkgdir/usr/bin/rtpengine
  install -Dm755 recording-daemon/rtpengine-recording $pkgdir/usr/bin/rtpengine-recording
  install -Dm755 iptables-extension/libxt_RTPENGINE.so $pkgdir/usr/lib/iptables/libxt_RTPENGINE.so
}

package_rtpengine-dkms() {
  depends=('linux-headers' 'dkms')
  cd "${srcdir}/$pkgbase-mr${pkgver}"
  # Copy dkms .conf
  install -Dm644 debian/dkms.conf.in "${pkgdir}/usr/src/${pkgbase}-${pkgver}/dkms.conf"
  cp -r kernel-module/* $pkgdir/usr/src/$pkgbase-$pkgver/

  # Set name and version
  sed -e "s/__VERSION__/${pkgver}/" \
    -e "s/ngcp-rtpengine/rtpengine/" \
    -i "${pkgdir}/usr/src/${pkgbase}-${pkgver}/dkms.conf"

}