Many legacy workloads still run on older Elasticsearch versions — particularly 5.x, 6.x, or 7.x — due to inertia, compatibility constraints, or lack of ownership. Once these versions exceed their standard support window, AWS begins charging an hourly Extended Support fee for each domain. These fees are often missed in cost reviews, especially in environments that are inactive but still provisioned. In aggregate, outdated Elasticsearch clusters contribute to significant silent spend unless proactively addressed.