After start tor-browser on debian wheezy it tried to upgrade to 6.5 version. It automatically downloaded asc, xz and failed on verifying. I made so several times, then go to https://dist.torproject.org/torbrowser/6.5/ and downloaded myself both. Both are same checked with diff3. After failed verifying, obviously, cannot upgrade. What can be reason? Thanks.
Solution for Debian Wheezy found following:
update/refresh keys from mit using command
gpg --keyserver pgp.mit.edu --homedir "$HOME/.local/share/torbrowser/gnupg_homedir/" --refresh-keys
torbrowser-launcher upgrades itself successfully.
Thanks to Vika^ from #tor