wget "${url_umatrix}"
 name=$(unzip -p "${umatrix_xpi}" manifest.json | jq -r .applications.gecko.id)
 mv "${umatrix_xpi}" "${name}".xpi
-tridactyl_version="1.17.1pre3455"
+tridactyl_version="1.17.1pre3355"
 tridactyl_xpi="tridactyl_beta-${tridactyl_version}-an+fx.xpi"
 url_tridactyl="https://tridactyl.cmcaine.co.uk/betas/${tridactyl_xpi}"
 wget "${url_tridactyl}"
 
 ./copy_dirtree.sh "${config_tree_buster}/home_files" "${HOME}" minimal user "${system_name}"
 
 # Set up native messenger for tridactyl.
-curl -fsSl https://raw.githubusercontent.com/tridactyl/tridactyl/78e662efefd1f4af2bdb2a53edecf03b535b997b/native/install.sh | bash
+version='ef9f02d0da258f68d7faf8898707f6d83d90d07a'
+curl -fsSl "https://raw.githubusercontent.com/tridactyl/tridactyl/${version}/native/install.sh" | bash
 
 # Set up further non-public parts of infrastructure.
 cd "${dir_secrets}"