To update Home Assistant Core installed in a python virtual environment (see Установка Home Assistant Core в виртуальное окружение python) you need to:

1. Stop the Home Assistant system service:

sudo systemctl stop home-assistant@$USER.service

where $USER is the login under which Home Assistant was installed

2. Go to the python virtual environment where Home Assistant Core was installed:

cd ~/homeassistant
source bin/activate

3. Download updates:

pip3 install --upgrade homeassistant

4. Exit the python virtual environment and start the Home Assistant system service:

deactivate
sudo systemctl start home-assistant@$USER.service