atftp software package provides advanced TFTP client, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install atftp
atftp is installed in your system.
Make ensure the atftp package were installed using the commands given below,
$ sudo dpkg-query -l | grep atftp *
You will get with atftp package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Network |
| Package | atftp |
| Version | 0.7.git20120829-3+b1 |
| Description | advanced TFTP client |
| Sub Section | Net |