If you want to run odoo8,9,10,11,12,13 on server, creating virtual environment is the solution for us.

Different odoo version requires different python version.

Below is easy steps to create virtual environment for you python and run odoo required version

Assuming current OS Ubuntu 16.04 with python 3.5 default.

I want to run odoo 13 with python3.6

NOTE: Make sure you have already installed python3.6

If not download from below URL
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lets install python3.6 (Ignore if already installed)

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Method 1

$ sudo add-apt-repository ppa:jonathonf/python-3.6
$ sudo apt-get update
$ sudo apt-get install python3.6


OR

Method 2

$ wget https://www.python.org/ftp/python/3.6.3/Python-3.6.3.tgz
$ tar -xvf Python-3.6.3.tgz
$ cd Python-3.6.3
$ sudo ./configure --enable-optimizations

$ sudo make -j8
$ sudo make install
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Lets create virtual environment and run odoo 13 with python 3.6
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STEP 1
sudo apt-get install python-virtualenv


STEP 2

virtualenv --python=python3.6 myvenv


STEP 3

source myvenv/bin/activate



STEP 4

Install python packages

cd /opt/odoo/

pip3 install -r requirement.txt


STEP 5

Configure .service file to run odoo with under virtual environment .

Add virtual environment  path under ExecStart variable


ExecStart= /pathofyourvirtualenv/bin/python3 /opt/odoo/odoo-bin -- config=/etc/odoo.conf --addons-path=/youraddonspath


STEP 6 systemctl start odoo.service


It is always recommended to use virtual environment for your python interpreter to run your odoo project in any version.