Projects on XL and larger compute add-ons can now create up to 5 Read Replicas.

[darora]

The initial launch of Read Replicas allowed for up to two Read Replicas per project.

The limit for projects on XL compute add-ons and larger has now been raised to 5 Read Replicas per project.

Projects on compute add-ons smaller than XL are still allowed up to 2 Read Replicas per project.