apache2-mpm-prefork software package provides transitional prefork MPM package for apache2, you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install apache2-mpm-prefork
apache2-mpm-prefork is installed in your system.
Make ensure the apache2-mpm-prefork package were installed using the commands given below,
$ sudo dpkg-query -l | grep apache2-mpm-prefork *
You will get with apache2-mpm-prefork package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Network |
| Package | apache2-mpm-prefork |
| Version | 2.4.7-1ubuntu4.13 [amd64, i386 |
| Description | transitional prefork MPM package for apache2 |
| Sub Section | Net |