javier-es:

• Device: TP-Link Archer C6 V2 EU version.
• Firmware version: OpenWrt 19.07.7 r11306-c4a6851c72 / LuCI openwrt-19.07 branch git-21.044.30835-34e0d65
• Kernel version: 4.14.221

I was trying to install wireguard and it's impossible because wireguard-tools isn't present in release repositories:

root@OpenWrt-casa:~# opkg install wireguard
Installing wireguard (1.0.20200611-2) to root...
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/base/wireguard_1.0.20200611-2_mips_24kc.ipk
Collected errors:

Obviously, I think that wireguard-tools should stay on https://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/base/ but it doesn't.

opkg update results:

root@OpenWrt-casa:~# opkg update
Downloading http://downloads.openwrt.org/releases/19.07.7/targets/ath79/generic/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_core
Downloading http://downloads.openwrt.org/releases/19.07.7/targets/ath79/generic/packages/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.7/targets/ath79/generic/kmods/4.14.221-1-b84a5a29b1d5ae1dc33ccf9ba292ca1d/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_kmods
Downloading http://downloads.openwrt.org/releases/19.07.7/targets/ath79/generic/kmods/4.14.221-1-b84a5a29b1d5ae1dc33ccf9ba292ca1d/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/base/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_base
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/base/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/freifunk/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_freifunk
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/freifunk/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/luci/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_luci
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/luci/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_packages
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/packages/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/routing/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_routing
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/routing/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/telephony/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_telephony
Downloading http://downloads.openwrt.org/releases/19.07.7/packages/mips_24kc/telephony/Packages.sig
Signature check passed.