Can I update Mac OS 10.11 to 10.11.6 using a dmg of the update? My internet connection is lame  and the last time I tried to update with the download through App store, it downloaded and restarted but said that the verification of the update package was unsuccessful . I don't want to do that again . 

So, I have manually downloaded the update package (1.55 GB) from http://supportdownload.apple.com. Now how do I update Mac OS , and also I don't want the verification failed kind of error. I also do know that this happens at some cases when OSx needs to be installed through the recovery section and you sure can fix it changing the systems date, but how do I do it in this case?
You can get the dmg file from here: https://support.apple.com/downloads/macos

While downloading the dmg please check the system requirement. Because you will need a combo dmg file if you are upgrading from say 10.11 to 10.11.6

On detail page of the dmg there is a System Requirements button at the bottom, please check the system requirement from there.

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Source: Ask Different