diff --git a/charts/ingress/templates/validation.tpl b/charts/ingress/templates/validation.tpl
index c4d3e34b7..6ac38be34 100644
--- a/charts/ingress/templates/validation.tpl
+++ b/charts/ingress/templates/validation.tpl
@@ -1,7 +1,51 @@
-{{- /* Validate 'expressions' router flavor is not used with KIC < 3.0 */}}
+{{- /* Validate 'expressions' router flavor is not used with KIC < 2.10 as it's not supported */}}
 {{- if and .Values.controller.ingressController.enabled
            (eq .Values.gateway.env.router_flavor "expressions")
-           (semverCompare "< 3.0" (include "kong.effectiveVersion" .Values.controller.ingressController.image))
+           (semverCompare "< 2.10" (include "kong.effectiveVersion" .Values.controller.ingressController.image))
 -}}
-    {{- fail (printf "expressions router flavor is not supported with ingress controller %s" .Values.controller.ingressController.image.tag ) -}}
+    {{- fail (printf `
+⚠️ Warning!
+
+"kong/ingress" chart in version 0.10.0 has introduced "gateway.env.router_flavor" value defaulting to "expressions".
+"expressions" router flavor is not supported with Kong Ingress Controller %q that you're using.
+
+✅ How to fix it (alternatives)
+
+1. Upgrade to Kong Ingress Controller 3.0 to use this feature.
+
+2. If you want to keep using your Kong Ingress Controller version, set "gateway.env.router_flavor" to "traditional" to
+backoff to the previous router flavor in your values.yaml:
+
+gateway:
+  env:
+    router_flavor: "traditional"` .Values.controller.ingressController.image.tag  ) -}}
+{{- end -}}
+
+{{- /* Validate that when 'expressions' router flavor is used with KIC < 3.0, feature flag must be set. */ -}}
+{{- if and (.Values.controller.ingressController.enabled)
+           (eq .Values.gateway.env.router_flavor "expressions")
+           (not (contains "ExpressionRoutes=true" (default "" .Values.controller.ingressController.env.feature_gates)))
+           (semverCompare "< 3.0" (include "kong.effectiveVersion" .Values.controller.ingressController.image)) -}}
+    {{- fail (printf `
+⚠️ Warning!
+
+"kong/ingress" chart in version 0.10.0 has introduced "gateway.env.router_flavor" value defaulting to "expressions".
+You're using Kong Ingress Controller version %q which supports this feature only when feature flag "ExpressionRoutes=true" is set.
+
+✅ How to fix it (alternatives)
+
+1. Upgrade to Kong Ingress Controller 3.0 to use this feature.
+
+2. Set "controller.ingressController.env.feature_gates" to "ExpressionRoutes=true" to enable this feature in your values.yaml:
+
+controller:
+  ingressController:
+    env:
+      feature_gates: "ExpressionRoutes=true"
+
+2. Set "gateway.env.router_flavor" to "traditional" to use the previous router flavor in your values.yaml:
+
+gateway:
+  env:
+    router_flavor: "traditional"` .Values.controller.ingressController.image.tag) -}}
 {{- end -}}