In both the 2.5 and 2.6 documentation, it incorrectly instructs the user to patch the DATABASE_URL environment variable for the pods and system-app pre hook.

 
The issue with this command is two fold:

1. It hardcodes the index as "1" for the patch ("/spec/strategy/rollingParams/pre/execNewPod/env/1/value"). This makes too much of an assumption and will rarely be correct in the case of upgrades. It's not even at index 1 for new installations from our template. 
2. With a fresh installation of 2.5 the value is stored in a secret. The docs should be having you update the secret, not the environment variable in multiple places. The docs appear to be correct in 2.7+