diff --git a/check_update.sh b/check_update.sh
new file mode 100755
index 0000000..17bd71b
--- /dev/null
+++ b/check_update.sh
@@ -0,0 +1,27 @@
+#!/bin/bash
+
+set -e
+
+SCRIPTDIR=$(cd $(dirname "${BASH_SOURCE[0]}") && pwd)
+
+# dummy toolchain variables
+export LINUXPKG="linux"
+
+# utilities
+source "$SCRIPTDIR/util/depends.sh"
+source "$SCRIPTDIR/util/version.sh"
+source "$SCRIPTDIR/util/misc.sh"
+
+# check all packages
+for pkg in $SCRIPTDIR/pkg/*; do
+	[ -d $pkg ] || continue;
+
+	name=$(basename $pkg)
+	echo "-- checking $name"
+	source "$pkg/build"
+
+	version=$(check_update)
+	if [ ! -z $version ]; then
+		echo "$name has newer version: $version"
+	fi
+done
diff --git a/pkg/bash-completion/build b/pkg/bash-completion/build
index a92095e..919e8c2 100755
--- a/pkg/bash-completion/build
+++ b/pkg/bash-completion/build
@@ -24,3 +24,10 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | \
+	    grep -o ">bash-completion-[0-9.]*tar.gz<" | grep -v "2008" |\
+	    sed 's/>bash-completion-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
diff --git a/pkg/bash/build b/pkg/bash/build
index c9d67fd..6b264b3 100755
--- a/pkg/bash/build
+++ b/pkg/bash/build
@@ -35,3 +35,9 @@ deploy() {
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 	rm -r "$DEPLOY/lib"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">bash-[0-9.]*tar.gz<" | \
+	    sed 's/>bash-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/bbstatic/build b/pkg/bbstatic/build
index ccb94a1..30e66d4 100755
--- a/pkg/bbstatic/build
+++ b/pkg/bbstatic/build
@@ -30,3 +30,10 @@ deploy() {
 	mkdir -p "$DEPLOY/bin"
 	cp "$PKGBUILDDIR/busybox" "$DEPLOY/bin"
 }
+
+check_update() {
+	curl --silent -L "$URL" | \
+	    grep -o ">busybox-[0-9.]*tar.bz2<" | \
+	    sed 's/>busybox-//g' | sed 's/.tar.bz2<//g' | \
+	    verson_find_greatest "$VERSION"
+}
diff --git a/pkg/bdb/build b/pkg/bdb/build
index 9ea82fc..6301daf 100755
--- a/pkg/bdb/build
+++ b/pkg/bdb/build
@@ -29,3 +29,9 @@ deploy() {
 	rm -r "$DEPLOY/docs"
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	# we need to login to access newer versions
+	# ... because Oracle, thats why!
+	return
+}
diff --git a/pkg/btrfs-progs/build b/pkg/btrfs-progs/build
index 9f0e4a6..057d33c 100755
--- a/pkg/btrfs-progs/build
+++ b/pkg/btrfs-progs/build
@@ -32,3 +32,10 @@ deploy() {
 	strip_files ${DEPLOY}/{bin,lib}/*
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | \
+	    grep -o ">btrfs-progs-v[0-9.]*tar.xz<" | \
+	    sed 's/>btrfs-progs-v//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/bzip2/build b/pkg/bzip2/build
index 1cbb92e..024681f 100755
--- a/pkg/bzip2/build
+++ b/pkg/bzip2/build
@@ -36,3 +36,9 @@ deploy() {
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 	rmdir "$DEPLOY/lib"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o "bzip2-[0-9.]*tar.gz" | \
+	    sed 's/bzip2-//g' | sed 's/.tar.gz//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/coreutils/build b/pkg/coreutils/build
index 52f12bb..6159f64 100755
--- a/pkg/coreutils/build
+++ b/pkg/coreutils/build
@@ -23,3 +23,9 @@ deploy() {
 	make DESTDIR="$DEPLOY" install-strip
 	rm -r "$DEPLOY/share" "$DEPLOY/lib"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">coreutils-[0-9.]*tar.xz<" | \
+	    sed 's/>coreutils-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/dhcpcd/build b/pkg/dhcpcd/build
index 1aae974..1528b57 100755
--- a/pkg/dhcpcd/build
+++ b/pkg/dhcpcd/build
@@ -34,3 +34,9 @@ deploy() {
 
 	rm -rf "$DEPLOY/usr"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">dhcpcd-[0-9.]*tar.xz<" | \
+	    sed 's/>dhcpcd-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/diffutils/build b/pkg/diffutils/build
index 28591c4..9d75092 100755
--- a/pkg/diffutils/build
+++ b/pkg/diffutils/build
@@ -23,3 +23,9 @@ deploy() {
 
 	rm -r "$DEPLOY/share" "$DEPLOY/lib"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">diffutils-[0-9.]*tar.xz<" | \
+	    sed 's/>diffutils-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/dnsmasq/build b/pkg/dnsmasq/build
index eff2d53..4690b0e 100644
--- a/pkg/dnsmasq/build
+++ b/pkg/dnsmasq/build
@@ -35,3 +35,9 @@ deploy() {
 
 	mkdir -p "$DEPLOY/etc/dnsmasq.d"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">dnsmasq-[0-9.]*tar.xz<" | \
+	    sed 's/>dnsmasq-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
diff --git a/pkg/dosfstools/build b/pkg/dosfstools/build
index 88c1430..48be96d 100755
--- a/pkg/dosfstools/build
+++ b/pkg/dosfstools/build
@@ -24,3 +24,10 @@ deploy() {
 	make DESTDIR="$DEPLOY" install-strip
 	rm -r "$DEPLOY/share"
 }
+
+check_update() {
+	curl --silent -L "https://github.com/dosfstools/dosfstools/releases" |\
+	    grep -o "dosfstools-[0-9.]*tar.xz" | \
+	    sed 's/dosfstools-//g' | sed 's/.tar.xz//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/ethtool/build b/pkg/ethtool/build
index 900ca71..ca1f52b 100755
--- a/pkg/ethtool/build
+++ b/pkg/ethtool/build
@@ -23,3 +23,9 @@ deploy() {
 
 	rm -r "$DEPLOY/share"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o "ethtool-[0-9.]*tar.xz" | \
+	    sed 's/ethtool-//g' | sed 's/.tar.xz//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/eudev/build b/pkg/eudev/build
index 3812b10..118a101 100755
--- a/pkg/eudev/build
+++ b/pkg/eudev/build
@@ -31,3 +31,9 @@ deploy() {
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 	rmdir "$DEPLOY/share"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o "eudev-[0-9.]*tar.gz" | \
+	    sed 's/eudev-//g' | sed 's/.tar.gz//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/expat/build b/pkg/expat/build
index 988ba03..d662a3b 100644
--- a/pkg/expat/build
+++ b/pkg/expat/build
@@ -27,3 +27,12 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	local version=$(echo "$VERSION" | sed 's/R_//g' | sed 's/_/./g')
+
+	curl --silent -L "https://github.com/libexpat/libexpat/releases" | \
+	    grep -o "expat-[0-9.]*tar.bz2" | \
+	    sed 's/expat-//g' | sed 's/.tar.bz2//g' | \
+	    verson_find_greatest "$version"
+}
\ No newline at end of file
diff --git a/pkg/file/build b/pkg/file/build
index f2c4882..fc3a2ef 100755
--- a/pkg/file/build
+++ b/pkg/file/build
@@ -26,3 +26,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent --list-only "$URL/" | grep -o "file-[0-9.]*tar.gz" | \
+	    sed 's/file-//g' | sed 's/.tar.gz//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/findutils/build b/pkg/findutils/build
index 8c633ef..066ed39 100755
--- a/pkg/findutils/build
+++ b/pkg/findutils/build
@@ -24,3 +24,9 @@ deploy() {
 
 	rm -r "$DEPLOY/share" "$DEPLOY/lib"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">findutils-[0-9.]*tar.gz<" | \
+	    sed 's/>findutils-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/firmware-rpi3/build b/pkg/firmware-rpi3/build
index 0646b60..b538f80 100755
--- a/pkg/firmware-rpi3/build
+++ b/pkg/firmware-rpi3/build
@@ -32,3 +32,9 @@ deploy() {
 	strip_files ${DEPLOY}/opt/vc/lib/*.so
 	strip_files ${DEPLOY}/opt/vc/lib/plugins/*.so
 }
+
+check_update() {
+	curl --silent -L https://github.com/raspberrypi/firmware/releases | \
+	     grep -o "[0-9.]\+tar.gz" | sed 's/.tar.gz//g' | \
+	     verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/gawk/build b/pkg/gawk/build
index 21ca92a..fea8d06 100755
--- a/pkg/gawk/build
+++ b/pkg/gawk/build
@@ -24,3 +24,9 @@ deploy() {
 	rm "$DEPLOY/bin/gawk-$VERSION"
 	rm -r "$DEPLOY/include" "$DEPLOY/share/info" "$DEPLOY/share/man"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">gawk-[0-9.]*tar.xz<" | \
+	    sed 's/>gawk-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/gmp/build b/pkg/gmp/build
index fe772b9..6400c24 100755
--- a/pkg/gmp/build
+++ b/pkg/gmp/build
@@ -27,3 +27,9 @@ deploy() {
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 	strip_files ${DEPLOY}/lib/*.so*
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">gmp-[0-9.]*tar.bz2<" | \
+	    sed 's/>gmp-//g' | sed 's/.tar.bz2<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/grep/build b/pkg/grep/build
index 104b029..2648aef 100755
--- a/pkg/grep/build
+++ b/pkg/grep/build
@@ -22,3 +22,9 @@ deploy() {
 	make DESTDIR="$DEPLOY" install-strip
 	rm -r "$DEPLOY/share" "$DEPLOY/lib"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">grep-[0-9.]*tar.xz<" | \
+	    sed 's/>grep-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/gzip/build b/pkg/gzip/build
index 0c7d6e6..edb301b 100755
--- a/pkg/gzip/build
+++ b/pkg/gzip/build
@@ -22,3 +22,9 @@ deploy() {
 	make DESTDIR="$DEPLOY" install-strip
 	rm -r "$DEPLOY/share"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">gzip-[0-9.]*tar.xz<" | \
+	    sed 's/>gzip-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/iana-etc/build b/pkg/iana-etc/build
index 38cefe4..2fa8c3a 100755
--- a/pkg/iana-etc/build
+++ b/pkg/iana-etc/build
@@ -21,3 +21,7 @@ deploy() {
 	cp "$SOURCE/protocols" "$DEPLOY/etc"
 	cp "$SOURCE/services" "$DEPLOY/etc"
 }
+
+check_update() {
+	return
+}
\ No newline at end of file
diff --git a/pkg/inetutils/build b/pkg/inetutils/build
index c48e15f..5125608 100755
--- a/pkg/inetutils/build
+++ b/pkg/inetutils/build
@@ -27,3 +27,9 @@ deploy() {
 	rm -r "$DEPLOY/share" "$DEPLOY/lib"
 	(rmdir "$DEPLOY/libexec" || true) 2> /dev/null ;
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">inetutils-[0-9.]*tar.xz<" | \
+	    sed 's/>inetutils-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/init/build b/pkg/init/build
index bec0b8a..6729e83 100755
--- a/pkg/init/build
+++ b/pkg/init/build
@@ -71,3 +71,7 @@ deploy() {
 
 	unset -v i GETTY_TTY HWCLOCK DHCP_PORTS
 }
+
+check_update() {
+	return
+}
\ No newline at end of file
diff --git a/pkg/initrd/build b/pkg/initrd/build
index 22fa4f0..3136d1f 100755
--- a/pkg/initrd/build
+++ b/pkg/initrd/build
@@ -26,3 +26,7 @@ slink /bin/sh /bin/busybox 0777 0 0
 file /init $DEPLOY/init 0775 0 0
 _EOF
 }
+
+check_update() {
+	return
+}
\ No newline at end of file
diff --git a/pkg/iproute2/build b/pkg/iproute2/build
index 4af3888..0342381 100755
--- a/pkg/iproute2/build
+++ b/pkg/iproute2/build
@@ -27,3 +27,9 @@ deploy() {
 
 	strip_files ${DEPLOY}/bin/*
 }
+
+check_update() {
+	curl --silent -L $URL | grep -o "iproute2-[0-9.]*tar.xz" | \
+	    sed 's/iproute2-//g' | sed 's/.tar.xz//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/kbd/build b/pkg/kbd/build
index 7813f82..5131673 100755
--- a/pkg/kbd/build
+++ b/pkg/kbd/build
@@ -27,3 +27,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">kbd-[0-9.]*tar.xz<" | \
+	    sed 's/>kbd-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/kmod/build b/pkg/kmod/build
index 43aeebe..481643d 100644
--- a/pkg/kmod/build
+++ b/pkg/kmod/build
@@ -32,3 +32,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">kmod-[0-9.]*tar.xz<" | \
+	    sed 's/>kmod-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/less/build b/pkg/less/build
index 06b8f16..ff40df7 100755
--- a/pkg/less/build
+++ b/pkg/less/build
@@ -25,3 +25,9 @@ deploy() {
 
 	rm -r "$DEPLOY/share"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">less-[0-9.]*tar.gz<" | \
+	    sed 's/>less-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/libbsd/build b/pkg/libbsd/build
index 9f675ed..9f6e50e 100644
--- a/pkg/libbsd/build
+++ b/pkg/libbsd/build
@@ -26,3 +26,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">libbsd-[0-9.]*tar.xz<" | \
+	    sed 's/>libbsd-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/libevent/build b/pkg/libevent/build
index 8e71a6d..8fb1cda 100755
--- a/pkg/libevent/build
+++ b/pkg/libevent/build
@@ -27,3 +27,9 @@ deploy() {
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 	strip_files ${DEPLOY}/lib/*
 }
+
+check_update() {
+	curl --silent -L https://github.com/libevent/libevent/releases | \
+	    grep -o "libevent-[0-9.]*-stable" | grep -o "[0-9.]*" | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/libiconv/build b/pkg/libiconv/build
index a8f06bd..5de9964 100755
--- a/pkg/libiconv/build
+++ b/pkg/libiconv/build
@@ -28,3 +28,9 @@ deploy() {
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 	strip_files ${DEPLOY}/{bin,lib}/*
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">libiconv-[0-9.]*tar.gz<" | \
+	    sed 's/>libiconv-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/libidn2/build b/pkg/libidn2/build
index 22697bd..ee15f2f 100755
--- a/pkg/libidn2/build
+++ b/pkg/libidn2/build
@@ -26,3 +26,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">libidn2-[0-9.]*tar.gz<" | \
+	    sed 's/>libidn2-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/libmnl/build b/pkg/libmnl/build
index c4216fa..ef56261 100644
--- a/pkg/libmnl/build
+++ b/pkg/libmnl/build
@@ -24,3 +24,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">libmnl-[0-9.]*tar.bz2<" | \
+	    sed 's/>libmnl-//g' | sed 's/.tar.bz2<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/libnftnl/build b/pkg/libnftnl/build
index 29ef999..d7307fb 100644
--- a/pkg/libnftnl/build
+++ b/pkg/libnftnl/build
@@ -24,3 +24,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">libnftnl-[0-9.]*tar.bz2<" | \
+	    sed 's/>libnftnl-//g' | sed 's/.tar.bz2<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/libseccomp/build b/pkg/libseccomp/build
index b7e62ed..d33f84d 100644
--- a/pkg/libseccomp/build
+++ b/pkg/libseccomp/build
@@ -26,3 +26,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L https://github.com/seccomp/libseccomp/releases | \
+	    grep -o "libseccomp-[0-9.]*tar.gz" | sed 's/libseccomp-//g' | \
+	    sed 's/.tar.gz//g' | verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/libtasn1/build b/pkg/libtasn1/build
index bfbd7b0..9db4dbc 100755
--- a/pkg/libtasn1/build
+++ b/pkg/libtasn1/build
@@ -26,3 +26,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">libtasn1-[0-9.]*tar.gz<" | \
+	    sed 's/>libtasn1-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/libunistring/build b/pkg/libunistring/build
index 03fad5b..948df9a 100755
--- a/pkg/libunistring/build
+++ b/pkg/libunistring/build
@@ -27,3 +27,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">libunistring-[0-9.]*tar.xz<" | \
+	    sed 's/>libunistring-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/linux-rpi3/build b/pkg/linux-rpi3/build
index dea2155..76f4dcc 100755
--- a/pkg/linux-rpi3/build
+++ b/pkg/linux-rpi3/build
@@ -32,3 +32,12 @@ deploy() {
 
 	install -m 755 "arch/arm/boot/zImage" "$DEPLOY/vmlinuz"
 }
+
+check_update() {
+	local version=$(echo $VERSION | sed 's/-[0-9]*$//g')
+
+	curl --silent -L "https://github.com/raspberrypi/linux/releases" | \
+	    grep -o "raspberrypi-kernel_[0-9.]*-[0-9]" | \
+	    sed 's/raspberrypi-kernel_//g' | sed 's/-/./g' | \
+	    verson_find_greatest "$version"
+}
\ No newline at end of file
diff --git a/pkg/linux/build b/pkg/linux/build
index 9ed3de3..61f1d32 100755
--- a/pkg/linux/build
+++ b/pkg/linux/build
@@ -34,3 +34,10 @@ deploy() {
 
 	install -m 755 "arch/$LINUX_CPU/boot/$LINUX_TGT" "$DEPLOY/vmlinuz"
 }
+
+check_update() {
+	curl --silent -L https://www.kernel.org/ | \
+	    grep -o linux-[0-9.]*tar.xz | \
+	    sed 's/linux-//g' | sed 's/.tar.xz//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/lzo/build b/pkg/lzo/build
index 1a04f19..c74749c 100644
--- a/pkg/lzo/build
+++ b/pkg/lzo/build
@@ -27,3 +27,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">lzo-[0-9.]*tar.gz<" | \
+	    sed 's/>lzo-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/musl/build b/pkg/musl/build
index 64b0120..74adf50 100755
--- a/pkg/musl/build
+++ b/pkg/musl/build
@@ -32,3 +32,9 @@ deploy() {
 
 	strip_files ${DEPLOY}/lib/*
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">musl-[0-9.]*tar.gz<" | \
+	    sed 's/>musl-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/nano/build b/pkg/nano/build
index 676eb77..dfd7bd1 100644
--- a/pkg/nano/build
+++ b/pkg/nano/build
@@ -23,3 +23,9 @@ deploy() {
 
 	rm -r "$DEPLOY/share" "$DEPLOY/lib"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">nano-[0-9.]*tar.xz<" | \
+	    sed 's/>nano-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/ncurses/build b/pkg/ncurses/build
index 411cd85..cf96636 100755
--- a/pkg/ncurses/build
+++ b/pkg/ncurses/build
@@ -69,3 +69,9 @@ deploy() {
 
 	rm -r "$olddir"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">ncurses-[0-9.]*tar.gz<" | \
+	    sed 's/>ncurses-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/nettle/build b/pkg/nettle/build
index 1388802..479901c 100755
--- a/pkg/nettle/build
+++ b/pkg/nettle/build
@@ -25,3 +25,9 @@ deploy() {
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 	strip_files ${DEPLOY}/{bin,lib}/*
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">nettle-[0-9.]*tar.gz<" | \
+	    sed 's/>nettle-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/nftables/build b/pkg/nftables/build
index 088575c..a0e4329 100644
--- a/pkg/nftables/build
+++ b/pkg/nftables/build
@@ -23,3 +23,9 @@ deploy() {
 
 	make DESTDIR="$DEPLOY" install-strip
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">nftables-[0-9.]*tar.bz2<" | \
+	    sed 's/>nftables-//g' | sed 's/.tar.bz2<//g' | grep -v 0.099 |\
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/openssh/build b/pkg/openssh/build
index 7084e6a..63dea18 100644
--- a/pkg/openssh/build
+++ b/pkg/openssh/build
@@ -35,3 +35,11 @@ deploy() {
 
 	install -v -m755 "$SOURCE/contrib/ssh-copy-id" "$DEPLOY/bin"
 }
+
+check_update() {
+	local version=$(echo $VERSION | sed 's/p/./g')
+
+	curl --silent -L "$URL" | grep -o ">openssh-[0-9.]*p[0-9]*.tar.gz<" | \
+	    sed 's/>openssh-//g' | sed 's/.tar.gz<//g' | sed 's/p/./g' | \
+	    verson_find_greatest "$version"
+}
\ No newline at end of file
diff --git a/pkg/openssl/build b/pkg/openssl/build
index 06dc82f..26b3cd8 100755
--- a/pkg/openssl/build
+++ b/pkg/openssl/build
@@ -31,3 +31,12 @@ deploy() {
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 	strip_files ${DEPLOY}/bin/* ${DEPLOY}/lib/*.so*
 }
+
+check_update() {
+	local version=$(echo $VERSION | sed 's/\([[:lower:]]\)/.\1/g')
+
+	curl --silent -L "$URL" | grep -o ">openssl-[0-9a-z.]*tar.gz<" | \
+	    sed 's/>openssl-//g' | sed 's/.tar.gz<//g' | \
+	    sed 's/\([[:lower:]]\)/.\1/g' | \
+	    verson_find_greatest "$version"
+}
\ No newline at end of file
diff --git a/pkg/procps-ng/build b/pkg/procps-ng/build
index 4685abe..6728f25 100755
--- a/pkg/procps-ng/build
+++ b/pkg/procps-ng/build
@@ -30,3 +30,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">procps-ng-[0-9.]*tar.xz<" | \
+	    sed 's/>procps-ng-//g' | sed 's/.tar.xz<//g' |\
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/psmisc/build b/pkg/psmisc/build
index 9e3a848..6fdb58b 100755
--- a/pkg/psmisc/build
+++ b/pkg/psmisc/build
@@ -26,3 +26,9 @@ deploy() {
 	make DESTDIR="$DEPLOY" install-strip
 	rm -r "$DEPLOY/share"
 }
+
+check_update() {
+	curl --silent -L $URL | grep -o ">psmisc-[0-9.]*tar.xz<" | \
+	    sed 's/>psmisc-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/readline/build b/pkg/readline/build
index 0e47b9c..8a2a7f8 100755
--- a/pkg/readline/build
+++ b/pkg/readline/build
@@ -28,3 +28,9 @@ deploy() {
 	chmod 755 ${DEPLOY}/lib/*
 	strip_files ${DEPLOY}/lib/*
 }
+
+check_update() {
+	curl --silent -L $URL | grep -o ">readline-[0-9.]*tar.gz<" | \
+	    sed 's/>readline-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/release-alix/build b/pkg/release-alix/build
index 9c26a19..73ed91c 100755
--- a/pkg/release-alix/build
+++ b/pkg/release-alix/build
@@ -35,3 +35,7 @@ deploy() {
 
 	tar czf "$DEPLOY/$PKGNAME.tar.gz" *
 }
+
+check_update() {
+	return
+}
\ No newline at end of file
diff --git a/pkg/release-rpi3/build b/pkg/release-rpi3/build
index 3f582a5..19fdeae 100755
--- a/pkg/release-rpi3/build
+++ b/pkg/release-rpi3/build
@@ -36,3 +36,7 @@ deploy() {
 
 	tar czf "$DEPLOY/$PKGNAME.tar.gz" *
 }
+
+check_update() {
+	return
+}
\ No newline at end of file
diff --git a/pkg/rootfs/build b/pkg/rootfs/build
index c67f555..d39fdb8 100755
--- a/pkg/rootfs/build
+++ b/pkg/rootfs/build
@@ -59,3 +59,7 @@ deploy() {
 	find $PKGBUILDDIR/{bin,lib,share} -type d -exec chmod u+w {} \;
 	find $PKGBUILDDIR/{bin,lib,share} -type f -exec chmod u+w {} \;
 }
+
+check_update() {
+	return
+}
\ No newline at end of file
diff --git a/pkg/sed/build b/pkg/sed/build
index 8e05bac..420a656 100755
--- a/pkg/sed/build
+++ b/pkg/sed/build
@@ -23,3 +23,9 @@ deploy() {
 
 	rm -r "$DEPLOY/share" "$DEPLOY/lib"
 }
+
+check_update() {
+	curl --silent -L $URL | grep -o ">sed-[0-9.]*tar.xz<" | \
+	    sed 's/>sed-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/shadow/build b/pkg/shadow/build
index 980e630..3d6d6da 100755
--- a/pkg/shadow/build
+++ b/pkg/shadow/build
@@ -38,3 +38,10 @@ deploy() {
 
 	rm $DEPLOY/bin/{vigr,vipw,chsh}
 }
+
+check_update() {
+	curl --silent -L https://github.com/shadow-maint/shadow/releases | \
+	    grep -o "shadow-[0-9.]*tar.xz" | \
+	    sed 's/shadow-//g' | sed 's/.tar.xz//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/sqlite3/build b/pkg/sqlite3/build
index ec7cfe8..bff2d18 100755
--- a/pkg/sqlite3/build
+++ b/pkg/sqlite3/build
@@ -26,3 +26,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L https://sqlite.org/download.html | \
+	    grep -o sqlite-autoconf-[0-9]*.tar.gz | grep -o [0-9]* | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/tar/build b/pkg/tar/build
index 40b8c64..3b11b73 100755
--- a/pkg/tar/build
+++ b/pkg/tar/build
@@ -23,3 +23,9 @@ deploy() {
 
 	rm -r "$DEPLOY/share" "$DEPLOY/lib"
 }
+
+check_update() {
+	curl --silent -L $URL | grep -o ">tar-[0-9.]*tar.xz<" | \
+	    sed 's/>tar-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/tc-binutils/build b/pkg/tc-binutils/build
index 1427dc2..c9f0150 100755
--- a/pkg/tc-binutils/build
+++ b/pkg/tc-binutils/build
@@ -20,3 +20,9 @@ build() {
 deploy() {
 	make install
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">binutils-[0-9.]*tar.xz<" | \
+	    sed 's/>binutils-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/tc-cloog/build b/pkg/tc-cloog/build
index 0b3e14e..400e1ed 100755
--- a/pkg/tc-cloog/build
+++ b/pkg/tc-cloog/build
@@ -16,3 +16,9 @@ build() {
 deploy() {
 	return
 }
+
+check_update() {
+	curl --silent --list-only "$URL/" | grep -o "cloog-[0-9.]*tar.gz" | \
+	    sed 's/cloog-//g' | sed 's/.tar.gz//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/tc-gcc1/build b/pkg/tc-gcc1/build
index 0598b61..2ad0be9 100755
--- a/pkg/tc-gcc1/build
+++ b/pkg/tc-gcc1/build
@@ -40,3 +40,10 @@ build() {
 deploy() {
 	make install-gcc install-target-libgcc
 }
+
+check_update() {
+	curl --silent -L "http://ftp.gnu.org/gnu/gcc" | \
+	    grep -o ">gcc-[0-9.]*/<" | \
+	    sed 's/>gcc-//g' | sed 's/\/<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/tc-gmp/build b/pkg/tc-gmp/build
index 17a9c14..9459aad 100755
--- a/pkg/tc-gmp/build
+++ b/pkg/tc-gmp/build
@@ -1,8 +1,5 @@
-VERSION="6.1.2"
-SRCDIR="gmp-$VERSION"
-TARBALL="gmp-$VERSION.tar.bz2"
-URL="http://ftp.gnu.org/gnu/gmp"
-SHA256SUM="5275bb04f4863a13516b2f39392ac5e272f5e1bb8057b18aec1c9b79d73d8fb2"
+# inherit package details from target GMP package
+source "$SCRIPTDIR/pkg/gmp/build"
 DEPENDS=""
 
 prepare() {
@@ -15,4 +12,4 @@ build() {
 
 deploy() {
 	return
-}
+}
\ No newline at end of file
diff --git a/pkg/tc-isl/build b/pkg/tc-isl/build
index be513f5..042bc47 100755
--- a/pkg/tc-isl/build
+++ b/pkg/tc-isl/build
@@ -16,3 +16,9 @@ build() {
 deploy() {
 	return
 }
+
+check_update() {
+	curl --silent --list-only "$URL/" | grep -o "isl-[0-9.]*tar.bz2" | \
+	    sed 's/isl-//g' | sed 's/.tar.bz2//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/tc-mpc/build b/pkg/tc-mpc/build
index 7ddb9cf..f504212 100755
--- a/pkg/tc-mpc/build
+++ b/pkg/tc-mpc/build
@@ -16,3 +16,9 @@ build() {
 deploy() {
 	return
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">mpc-[0-9.]*tar.gz<" | \
+	    sed 's/>mpc-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/tc-mpfr/build b/pkg/tc-mpfr/build
index a1f3498..95ba8fc 100755
--- a/pkg/tc-mpfr/build
+++ b/pkg/tc-mpfr/build
@@ -16,3 +16,9 @@ build() {
 deploy() {
 	return
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">mpfr-[0-9.]*tar.xz<" | \
+	    sed 's/>mpfr-//g' | sed 's/.tar.xz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/tc-pkg-config/build b/pkg/tc-pkg-config/build
index b0b1712..d52baf6 100755
--- a/pkg/tc-pkg-config/build
+++ b/pkg/tc-pkg-config/build
@@ -27,3 +27,9 @@ deploy() {
 
 	ln -s pkg-config "$TCDIR/bin/$TARGET-pkg-config"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">pkg-config-[0-9.]*tar.gz<" | \
+	    sed 's/>pkg-config-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/toolchain/build b/pkg/toolchain/build
index f9a9806..8c6bb9a 100755
--- a/pkg/toolchain/build
+++ b/pkg/toolchain/build
@@ -23,3 +23,7 @@ set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
 _EOF
 	save_toolchain
 }
+
+check_update() {
+	return
+}
\ No newline at end of file
diff --git a/pkg/unbound/build b/pkg/unbound/build
index 14f229d..b843990 100644
--- a/pkg/unbound/build
+++ b/pkg/unbound/build
@@ -40,3 +40,9 @@ _EOF
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 	strip_files ${DEPLOY}/{bin,lib}/*
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o ">unbound-[0-9.]*tar.gz<" | \
+	    sed 's/>unbound-//g' | sed 's/.tar.gz<//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/util-linux/build b/pkg/util-linux/build
index 6bc3446..958dfa6 100755
--- a/pkg/util-linux/build
+++ b/pkg/util-linux/build
@@ -61,3 +61,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "https://www.kernel.org/pub/linux/utils/util-linux" | \
+	    grep -o "v[0-9.]*/" | grep -o "[0-9.]*" | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/xz/build b/pkg/xz/build
index 5a7406e..03a9d61 100644
--- a/pkg/xz/build
+++ b/pkg/xz/build
@@ -26,3 +26,9 @@ deploy() {
 
 	split_dev_deploy "$DEPLOY" "$DEVDEPLOY"
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o "xz-[0-9.]*tar.xz" | \
+	    sed 's/xz-//g' | sed 's/.tar.xz//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/pkg/zlib/build b/pkg/zlib/build
index 2f2b9c8..2fdc2a0 100644
--- a/pkg/zlib/build
+++ b/pkg/zlib/build
@@ -28,3 +28,9 @@ deploy() {
 
 	rm -r ${DEPLOY}/share
 }
+
+check_update() {
+	curl --silent -L "$URL" | grep -o "xz-[0-9.]*tar.xz" | \
+	    sed 's/zlib-//g' | sed 's/.tar.xz//g' | \
+	    verson_find_greatest "$VERSION"
+}
\ No newline at end of file
diff --git a/util/depends.sh b/util/depends.sh
index 3a4a8cd..cb12dd2 100755
--- a/util/depends.sh
+++ b/util/depends.sh
@@ -1,7 +1,7 @@
 include_pkg() {
 	PKGNAME="$1"		# globally visible package name
 
-	unset -f build deploy prepare
+	unset -f build deploy prepare check_update
 	unset -v VERSION TARBALL URL SRCDIR SHA256SUM DEPENDS
 	source "$SCRIPTDIR/pkg/$PKGNAME/build"
 }
diff --git a/util/version.sh b/util/version.sh
new file mode 100644
index 0000000..1c6131e
--- /dev/null
+++ b/util/version.sh
@@ -0,0 +1,33 @@
+get_version_field() {
+	local field=$(echo "$1" | cut -d. -f$2 | sed 's/^0*//')
+
+	if [ -z $field ]; then
+		field="0"
+	fi
+
+	case "$field" in
+	[a-zA-Z]) printf '%d' "'$field'" ;;
+	*) echo "$field" ;;
+	esac
+}
+
+verson_find_greatest() {
+	local version i v V
+	local found="$1"
+
+	while read version; do
+		for i in 1 2 3 4; do
+			v=$(get_version_field $version $i)
+			V=$(get_version_field $found $i)
+			[ $v -ge $V ] || break
+			if [ $v -gt $V ]; then
+			    found="$version"
+			    break
+			fi
+		done
+	done
+
+	if [ "$found" != "$1" ]; then
+		echo "$found"
+	fi
+}