Jun 5, 2018 · May 29, 2018
diff --git a/_practicalities/intro.md b/_practicalities/intro.md
 be a difficult to debug and fix. Get inspiration from the message of failure at
 runtime, and adapt for installation time.


 Here is for a simple version of how IPython handle old versions of Python and
 Pip that still try to install IPython 7.0+ on Python `< (3,4)`.

 ```python
 if sys.version_info < (3, 4):

    error = """
    IPython 7.0+ supports Python 3.4 and above.
    When using Python 2.7, please install IPython 5.x LTS Long Term Support version.
    Python 3.3 was supported up to IPython 6.x.

    See IPython `README.rst` file for more information:

    https://github.com/ipython/ipython/blob/master/README.rst

    Python {py} detected.

    Try upgrading pip and retry.
    """.format(py='.'.join([str(v) for v in sys.version_info[:3]]))

    print(error, file=sys.stderr)
    sys.exit(1)
 ```

 You can look at the [full
 check](https://github.com/ipython/ipython/blob/6a3e2db0c299dc05e636653c4a43d0aa756fb1c8/setup.py#L23-L58)
 that attempt to detect which version of pip is in used.

 ## Fix dependant libraries

 If you control dependant packages, Make sure to include conditional dependencies
Original file line number	Diff line number	Diff line change
Expand Up		@@ -284,6 +284,35 @@ Otherwise user code can fail at runtime arbitrarily later in the future, which c
		be a difficult to debug and fix. Get inspiration from the message of failure at
		runtime, and adapt for installation time.


		Here is for a simple version of how IPython handle old versions of Python and
		Pip that still try to install IPython 7.0+ on Python `< (3,4)`.

		```python
		if sys.version_info < (3, 4):

		error = """
		IPython 7.0+ supports Python 3.4 and above.
		When using Python 2.7, please install IPython 5.x LTS Long Term Support version.
		Python 3.3 was supported up to IPython 6.x.

		See IPython `README.rst` file for more information:

		https://github.com/ipython/ipython/blob/master/README.rst

		Python {py} detected.

		Try upgrading pip and retry.
		""".format(py='.'.join([str(v) for v in sys.version_info[:3]]))

		print(error, file=sys.stderr)
		sys.exit(1)
		```

		You can look at the [full
		check](https://github.com/ipython/ipython/blob/6a3e2db0c299dc05e636653c4a43d0aa756fb1c8/setup.py#L23-L58)
		that attempt to detect which version of pip is in used.

		## Fix dependant libraries

		If you control dependant packages, Make sure to include conditional dependencies
Expand Down