Changelog extracted from README file:

What's new in ppp-2.4.1.
************************

* Pppd can now print out the set of options that are in effect.  The
  new `dump' option causes pppd to print out the option values after
  option parsing is complete.  The `dryrun' option causes pppd to
  print the options and then exit.

* The option parsing code has been fixed so that options in the
  per-tty options file are parsed correctly, and don't override values
  from the command line in most cases.

* The plugin option now looks in /usr/lib/pppd/<pppd-version> (for
  example, /usr/lib/pppd/2.4.1b1) for shared objects for plugins if
  there is no slash in the plugin name.

* When loading a plugin, pppd will now check the version of pppd for
  which the plugin was compiled, and refuse to load it if it is
  different to pppd's version string.  To enable this, the plugin
  source needs to #include "pppd.h" and have a line saying:
char pppd_version[] = VERSION;

* There is a bug in zlib, discovered by James Carlson, which can cause
  kernel memory corruption if Deflate is used with the lowest setting,
  8.  As a workaround pppd will now insist on using at least 9.

* Pppd should compile on Solaris and SunOS again.

* Pppd should now set the MTU correctly on demand-dialled interfaces.


What was new in ppp-2.4.0.
**************************

* Multilink: this package now allows you to combine multiple serial
  links into one logical link or `bundle', for increased bandwidth and
  reduced latency.  This is currently only supported under the
  Linux-2.3.99pre5 or later kernels.

* All the pppd processes running on a system now write information
  into a common database.  I used the `tdb' code from samba for this.

* New hooks have been added.

For a list of the changes made during the 2.3 series releases of this
package, see the Changes-2.3 file.