If a previously installed installation item needs to be updated there are two ways this can be done.

1 – Patching (minor update)
2 – Updating (major update)

Patching (minor update)

Patching an existing installation item means adding a small piece of software designed to fix problems to an already existing and installed installation item. One important thing to consider wether or not a software update will be handled as a patch or major update is how this software is being removed from the computer. When after a software update the original un-installation commands are being used to remove this software this update should be considered a patch installation. However, if the original software is being replaced after the update and the un-installation commands are changed the update should be considered a major update installation.

The following steps should be performed to patch an existing installation item:

1 – Copy the patch files
2 – Add new installation commands

1 – Copy the patch files

After you have determined that the update should be considered as a patch update you should copy the patch files to the existing source directory used by the already installed installation item. Make sure these files are added and not replaced over the already existing setup files. If these files use the same name as the existing files you should create a sub folder and copy these files in this sub folder or reconsider this update as a major update.

2 – Add new installation commands

Add the necessary (patch) commands to the existing installation commands and test these commands on a computer with the existing installation item installed and without the existing installation item installed. Both options should result in a successful installation with the patch included. Do not rename the installation item or change the existing installation commands or order. After the installation item is updated do not forget to redeploy the installation list.

Updating (major update)

Major updating an existing installation item means replacing the existing installation by a new installation with a higher version. One important thing to consider wether or not a software update will be handled as a major or patch update is how this software is being removed from the computer. When the original software is being replaced by a new installation and the un-installation commands are changed, the update should be considered a major update installation. However, if after a software update the original un-installation commands are being used to remove this software this update should be considered a patch installation.

The following steps should be performed to major update an existing installation item:

1 – Create a new installation item
2 – Expire the existing installation item
3 – Consider removing the existing installation item

1 – Create a new installation item

After you have determined that the update should be considered a major update you should copy the new setup files to a new source directory and create a new installation item. Make sure the membership options are the same as the existing installation item and that this installation item will install successfully on a computer with or without the existing installation item installed. Determine and set an availability date when the installation item will be installed. An example of a new installation item would be:

Before (existing): Adobe Reader 9

After (new): Adobe Reader 10

2 – Expire the existing installation item

After the new installation item is created you should expire the existing (old) installation item. Determine and set an expiration date before the availability date of the new installation item and set the Activate Uninstall Property to make sure that the existing installation item is removed before the new installation item is installed. Also, make sure the un-install commands are successfully tested. Do not forget to redeploy the installation list to make sure all changes are updated to all running ‘Easy Software Deployment Agents’.

3 – Consider removing the existing installation item

After the existing (old) installation item is successfully removed from all computers and the new installation item is successfully installed and no future control for this (old) installation item is needed you should export and then consider deleting this old installation item. Remember that both installation items will be logged by all running ‘Easy Software Deployment Agents’ that handled the old installation item. The old (removed) installation item will then be logged as Removed and the new installation item will be logged as Installed.