Upgrade 1.1.5 -> 1.1.6

[Evolution]

On upgrade,

Error: Can't create sql dump of database during backup

Also,

Enter Installation Key Here

Where do I find installation key?

[abolabo]

usually we publish message (notification) about upgrade with direct link that contain that installation key (message box below search field on abantecart control panel). But you can upgrade without it, manually.  All upgrade packages are available by key mask: abantecart_upgrade_XXX where XXX is new version without dots.
For ex.: abantecart_upgrade_117 

Also you can download upgrade package from our site (archive tar.gz ) and upload it on "upload extension" page.