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A new reply was posted to your ticket #11528 — "php warning: call-time pass-by-reference has been deprecated" by Nicholas K. Dionysopoulos (nicholas):
First, make sure that you have turned off the Debug System option in your Global Configuration. Then, go to Global Configuration, Server tab and set Error Reporting to None (this is the safest setting for live sites). Also note that I have already fixed this issue in the latest dev release of Akeeba Backup and this (proper) fix will make it into the next version.
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My Global Configuration is set as indicated above and I am still have the same problem.