как избежать этой ошибки, устанавливающей PHPMyAdmin на Ubuntu 16.04?

Недавно я обновил свой сервер от Ubuntu 14.04 до Ubuntu 16.04, но версия phpmyadmin по-прежнему равна 4.5, а я хочу установить 4.6 (для поддержки нового типа JSON).

Общие инструкции, которые я нахожу в Интернете, это добавить репозиторий nijel/phpmyadmin через apt-add-repository, но это дает мне странную ошибку.

 root@myserver:~# add-apt-repository ppa:nijel/phpmyadmin Latest phpMyAdmin packages - https://www.phpmyadmin.net/. Based on packages available in Debian. There are some notable changes: * it currently requires updated PHP packages, you can get packages from https://launchpad.net/~ondrej/+archive/ubuntu/php/ * it does include embedded copies of PHP libraries If you like phpMyAdmin, you can support it's further development at https://www.phpmyadmin.net/donate/ or https://www.phpmyadmin.net/sponsors/, thanks! More info: https://launchpad.net/~nijel/+archive/ubuntu/phpmyadmin Press [ENTER] to continue or ctrl-c to cancel adding it gpg: keyring `/tmp/tmp9zj2r1n2/secring.gpg' created gpg: keyring `/tmp/tmp9zj2r1n2/pubring.gpg' created gpg: requesting key 06ED541C from hkp server keyserver.ubuntu.com gpg: /tmp/tmp9zj2r1n2/trustdb.gpg: trustdb created gpg: key 06ED541C: public key "Launchpad PPA for Michal \xc4\x8ciha\xc5\x99" imported gpg: no ultimately trusted keys found gpg: Total number processed: 1 gpg: imported: 1 (RSA: 1) Exception in thread Thread-1: Traceback (most recent call last): File "/usr/lib/python3.5/threading.py", line 914, in _bootstrap_inner self.run() File "/usr/lib/python3.5/threading.py", line 862, in run self._target(*self._args, **self._kwargs) File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 688, in addkey_func func(**kwargs) File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 401, in add_key return apsk.add_ppa_signing_key() File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 271, in add_ppa_signing_key tmp_export_keyring, signing_key_fingerprint, tmp_keyring_dir): File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 220, in _verify_fingerprint got_fingerprints = self._get_fingerprints(keyring, keyring_dir) File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 212, in _get_fingerprints output = subprocess.check_output(cmd, universal_newlines=True) File "/usr/lib/python3.5/subprocess.py", line 626, in check_output **kwargs).stdout File "/usr/lib/python3.5/subprocess.py", line 695, in run stdout, stderr = process.communicate(input, timeout=timeout) File "/usr/lib/python3.5/subprocess.py", line 1059, in communicate stdout = self.stdout.read() File "/usr/lib/python3.5/encodings/ascii.py", line 26, in decode return codecs.ascii_decode(input, self.errors)[0] UnicodeDecodeError: 'ascii' codec can't decode byte 0xc4 in position 96: ordinal not in range(128) 

это выглядит как ошибка в программном обеспечении ppa, но я теряюсь на том, как это решить.