You can use open source tools like tfenv to upgrade terraform to a specific version.
Step 1: Install tfenv where terraform is installed
## Clone the tfenv project in your system
git clone https://github.com/tfutils/tfenv.git ~/.tfenv
## Add ~/.tfenv/bin to your $PATH
echo 'export PATH="$HOME/.tfenv/bin:$PATH"' >> ~/.bash_profile
Step 2: Upgrade terraform to a specific version
## Get available terraform version
## Upgrade terraform to a specific version
tfenv install 1.0.0
## Make the specific version as default
tfenv use 1.0.0
## Confirm terraform version
Note: If you are upgrading terraform version to a system where your terraform code is hosted, you also need to upgrade terraform code as each terraform major version has some syntactical changes in the way terraform configuration files are written. Please refer https://www.terraform.io/upgrade-guides/index.html for additional details.