diff --git a/src/main/kotlin/org/opensearch/indexmanagement/IndexManagementPlugin.kt b/src/main/kotlin/org/opensearch/indexmanagement/IndexManagementPlugin.kt
index b45281f91..0a6e8bccb 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/IndexManagementPlugin.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/IndexManagementPlugin.kt
@@ -150,14 +150,20 @@ internal class IndexManagementPlugin : JobSchedulerExtension, NetworkPlugin, Act
 
     companion object {
         const val PLUGIN_NAME = "opendistro-im"
-        const val OPEN_DISTRO_BASE_URI = "/_opendistro"
-        const val ISM_BASE_URI = "$OPEN_DISTRO_BASE_URI/_ism"
-        const val ROLLUP_BASE_URI = "$OPEN_DISTRO_BASE_URI/_rollup"
+        const val PLUGINS_BASE_URI = "/_plugins"
+        const val ISM_BASE_URI = "$PLUGINS_BASE_URI/_ism"
+        const val ROLLUP_BASE_URI = "$PLUGINS_BASE_URI/_rollup"
         const val POLICY_BASE_URI = "$ISM_BASE_URI/policies"
         const val ROLLUP_JOBS_BASE_URI = "$ROLLUP_BASE_URI/jobs"
         const val INDEX_MANAGEMENT_INDEX = ".opendistro-ism-config"
         const val INDEX_MANAGEMENT_JOB_TYPE = "opendistro-index-management"
         const val INDEX_STATE_MANAGEMENT_HISTORY_TYPE = "managed_index_meta_data"
+
+        const val OPEN_DISTRO_BASE_URI = "/_opendistro"
+        const val LEGACY_ISM_BASE_URI = "$OPEN_DISTRO_BASE_URI/_ism"
+        const val LEGACY_ROLLUP_BASE_URI = "$OPEN_DISTRO_BASE_URI/_rollup"
+        const val LEGACY_POLICY_BASE_URI = "$LEGACY_ISM_BASE_URI/policies"
+        const val LEGACY_ROLLUP_JOBS_BASE_URI = "$LEGACY_ROLLUP_BASE_URI/jobs"
     }
 
     override fun getJobIndex(): String = INDEX_MANAGEMENT_INDEX
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestAddPolicyAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestAddPolicyAction.kt
index 72b9d7a76..48d320466 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestAddPolicyAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestAddPolicyAction.kt
@@ -32,9 +32,11 @@ import org.opensearch.indexmanagement.indexstatemanagement.transport.action.addp
 import org.opensearch.client.node.NodeClient
 import org.opensearch.common.Strings
 import org.opensearch.common.xcontent.XContentHelper
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ISM_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.BaseRestHandler.RestChannelConsumer
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.POST
 import org.opensearch.rest.action.RestToXContentListener
@@ -45,9 +47,19 @@ class RestAddPolicyAction : BaseRestHandler() {
     override fun getName(): String = "add_policy_action"
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(POST, ADD_POLICY_BASE_URI),
-            Route(POST, "$ADD_POLICY_BASE_URI/{index}")
+            ReplacedRoute(
+                POST, ADD_POLICY_BASE_URI,
+                POST, LEGACY_ADD_POLICY_BASE_URI
+            ),
+            ReplacedRoute(
+                POST, "$ADD_POLICY_BASE_URI/{index}",
+                POST, "$LEGACY_ADD_POLICY_BASE_URI/{index}"
+            )
         )
     }
 
@@ -77,5 +89,6 @@ class RestAddPolicyAction : BaseRestHandler() {
 
     companion object {
         const val ADD_POLICY_BASE_URI = "$ISM_BASE_URI/add"
+        const val LEGACY_ADD_POLICY_BASE_URI = "$LEGACY_ISM_BASE_URI/add"
     }
 }
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestChangePolicyAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestChangePolicyAction.kt
index 411c7966d..1abae1ba1 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestChangePolicyAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestChangePolicyAction.kt
@@ -35,9 +35,11 @@ import org.opensearch.client.node.NodeClient
 import org.opensearch.common.Strings
 import org.opensearch.common.xcontent.XContentParser.Token
 import org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ISM_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.BaseRestHandler.RestChannelConsumer
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.POST
 import org.opensearch.rest.action.RestToXContentListener
@@ -48,9 +50,19 @@ class RestChangePolicyAction : BaseRestHandler() {
     private val log = LogManager.getLogger(javaClass)
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(POST, CHANGE_POLICY_BASE_URI),
-            Route(POST, "$CHANGE_POLICY_BASE_URI/{index}")
+            ReplacedRoute(
+                POST, CHANGE_POLICY_BASE_URI,
+                POST, LEGACY_CHANGE_POLICY_BASE_URI
+            ),
+            ReplacedRoute(
+                POST, "$CHANGE_POLICY_BASE_URI/{index}",
+                POST, "$LEGACY_CHANGE_POLICY_BASE_URI/{index}"
+            )
         )
     }
 
@@ -76,6 +88,7 @@ class RestChangePolicyAction : BaseRestHandler() {
 
     companion object {
         const val CHANGE_POLICY_BASE_URI = "$ISM_BASE_URI/change_policy"
+        const val LEGACY_CHANGE_POLICY_BASE_URI = "$LEGACY_ISM_BASE_URI/change_policy"
         const val INDEX_NOT_MANAGED = "This index is not being managed"
         const val INDEX_IN_TRANSITION = "Cannot change policy while transitioning to new state"
     }
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestDeletePolicyAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestDeletePolicyAction.kt
index 1cba59fd3..34ab2ea90 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestDeletePolicyAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestDeletePolicyAction.kt
@@ -32,8 +32,10 @@ import org.opensearch.indexmanagement.indexstatemanagement.transport.action.dele
 import org.opensearch.indexmanagement.util.REFRESH
 import org.opensearch.action.support.WriteRequest.RefreshPolicy
 import org.opensearch.client.node.NodeClient
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_POLICY_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.DELETE
 import org.opensearch.rest.action.RestStatusToXContentListener
@@ -42,8 +44,15 @@ import java.io.IOException
 class RestDeletePolicyAction : BaseRestHandler() {
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(DELETE, "$POLICY_BASE_URI/{policyID}")
+            ReplacedRoute(
+                DELETE, "$POLICY_BASE_URI/{policyID}",
+                DELETE, "$LEGACY_POLICY_BASE_URI/{policyID}"
+            )
         )
     }
 
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestExplainAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestExplainAction.kt
index 28d2cb7ef..465e0e415 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestExplainAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestExplainAction.kt
@@ -39,9 +39,11 @@ import org.apache.logging.log4j.LogManager
 import org.opensearch.action.support.master.MasterNodeRequest
 import org.opensearch.client.node.NodeClient
 import org.opensearch.common.Strings
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ISM_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.BaseRestHandler.RestChannelConsumer
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.GET
 import org.opensearch.rest.action.RestToXContentListener
@@ -52,12 +54,23 @@ class RestExplainAction : BaseRestHandler() {
 
     companion object {
         const val EXPLAIN_BASE_URI = "$ISM_BASE_URI/explain"
+        const val LEGACY_EXPLAIN_BASE_URI = "$LEGACY_ISM_BASE_URI/explain"
     }
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(GET, EXPLAIN_BASE_URI),
-            Route(GET, "$EXPLAIN_BASE_URI/{index}")
+            ReplacedRoute(
+                GET, EXPLAIN_BASE_URI,
+                GET, LEGACY_EXPLAIN_BASE_URI
+            ),
+            ReplacedRoute(
+                GET, "$EXPLAIN_BASE_URI/{index}",
+                GET, "$LEGACY_EXPLAIN_BASE_URI/{index}"
+            )
         )
     }
 
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestGetPolicyAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestGetPolicyAction.kt
index d3792eab1..cf1ca1c9d 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestGetPolicyAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestGetPolicyAction.kt
@@ -39,9 +39,12 @@ import org.opensearch.indexmanagement.indexstatemanagement.util.DEFAULT_QUERY_ST
 import org.opensearch.indexmanagement.indexstatemanagement.util.DEFAULT_SORT_ORDER
 import org.apache.logging.log4j.LogManager
 import org.opensearch.client.node.NodeClient
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_POLICY_BASE_URI
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ROLLUP_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.BaseRestHandler.RestChannelConsumer
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.GET
 import org.opensearch.rest.RestRequest.Method.HEAD
@@ -54,10 +57,23 @@ private val log = LogManager.getLogger(RestGetPolicyAction::class.java)
 class RestGetPolicyAction : BaseRestHandler() {
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(GET, POLICY_BASE_URI),
-            Route(GET, "$POLICY_BASE_URI/{policyID}"),
-            Route(HEAD, "$POLICY_BASE_URI/{policyID}")
+            ReplacedRoute(
+                GET, POLICY_BASE_URI,
+                GET, LEGACY_ROLLUP_BASE_URI
+            ),
+            ReplacedRoute(
+                GET, "$POLICY_BASE_URI/{policyID}",
+                GET, "$LEGACY_POLICY_BASE_URI/{policyID}"
+            ),
+            ReplacedRoute(
+                HEAD, "$POLICY_BASE_URI/{policyID}",
+                HEAD, "$LEGACY_POLICY_BASE_URI/{policyID}"
+            )
         )
     }
 
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestIndexPolicyAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestIndexPolicyAction.kt
index 80a139436..9df737974 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestIndexPolicyAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestIndexPolicyAction.kt
@@ -44,10 +44,12 @@ import org.opensearch.cluster.service.ClusterService
 import org.opensearch.common.settings.Settings
 import org.opensearch.common.xcontent.ToXContent
 import org.opensearch.index.seqno.SequenceNumbers
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_POLICY_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.BaseRestHandler.RestChannelConsumer
 import org.opensearch.rest.BytesRestResponse
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.PUT
 import org.opensearch.rest.RestResponse
@@ -70,9 +72,19 @@ class RestIndexPolicyAction(
     }
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(PUT, POLICY_BASE_URI),
-            Route(PUT, "$POLICY_BASE_URI/{policyID}")
+            ReplacedRoute(
+                PUT, POLICY_BASE_URI,
+                PUT, LEGACY_POLICY_BASE_URI
+            ),
+            ReplacedRoute(
+                PUT, "$POLICY_BASE_URI/{policyID}",
+                PUT, "$LEGACY_POLICY_BASE_URI/{policyID}"
+            )
         )
     }
 
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestRemovePolicyAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestRemovePolicyAction.kt
index 3a677db92..c9a63d18f 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestRemovePolicyAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestRemovePolicyAction.kt
@@ -31,8 +31,10 @@ import org.opensearch.indexmanagement.indexstatemanagement.transport.action.remo
 import org.opensearch.indexmanagement.indexstatemanagement.transport.action.removepolicy.RemovePolicyRequest
 import org.opensearch.client.node.NodeClient
 import org.opensearch.common.Strings
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ISM_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.POST
 import org.opensearch.rest.action.RestToXContentListener
@@ -41,9 +43,19 @@ import java.io.IOException
 class RestRemovePolicyAction : BaseRestHandler() {
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(POST, REMOVE_POLICY_BASE_URI),
-            Route(POST, "$REMOVE_POLICY_BASE_URI/{index}")
+            ReplacedRoute(
+                POST, REMOVE_POLICY_BASE_URI,
+                POST, LEGACY_REMOVE_POLICY_BASE_URI
+            ),
+            ReplacedRoute(
+                POST, "$REMOVE_POLICY_BASE_URI/{index}",
+                POST, "$LEGACY_REMOVE_POLICY_BASE_URI/{index}"
+            )
         )
     }
 
@@ -67,5 +79,6 @@ class RestRemovePolicyAction : BaseRestHandler() {
 
     companion object {
         const val REMOVE_POLICY_BASE_URI = "$ISM_BASE_URI/remove"
+        const val LEGACY_REMOVE_POLICY_BASE_URI = "$LEGACY_ISM_BASE_URI/remove"
     }
 }
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestRetryFailedManagedIndexAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestRetryFailedManagedIndexAction.kt
index 12f2c35c5..d22c4b61d 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestRetryFailedManagedIndexAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestRetryFailedManagedIndexAction.kt
@@ -34,9 +34,11 @@ import org.opensearch.action.support.master.MasterNodeRequest.DEFAULT_MASTER_NOD
 import org.opensearch.client.node.NodeClient
 import org.opensearch.common.Strings
 import org.opensearch.common.xcontent.XContentHelper
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ISM_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.BaseRestHandler.RestChannelConsumer
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.POST
 import org.opensearch.rest.action.RestToXContentListener
@@ -46,9 +48,19 @@ class RestRetryFailedManagedIndexAction : BaseRestHandler() {
     private val log = LogManager.getLogger(javaClass)
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(POST, RETRY_BASE_URI),
-            Route(POST, "$RETRY_BASE_URI/{index}")
+            ReplacedRoute(
+                POST, RETRY_BASE_URI,
+                POST, LEGACY_RETRY_BASE_URI
+            ),
+            ReplacedRoute(
+                POST, "$RETRY_BASE_URI/{index}",
+                POST, "$LEGACY_RETRY_BASE_URI/{index}"
+            )
         )
     }
 
@@ -78,5 +90,6 @@ class RestRetryFailedManagedIndexAction : BaseRestHandler() {
 
     companion object {
         const val RETRY_BASE_URI = "$ISM_BASE_URI/retry"
+        const val LEGACY_RETRY_BASE_URI = "$LEGACY_ISM_BASE_URI/retry"
     }
 }
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/refreshanalyzer/RestRefreshSearchAnalyzerAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/refreshanalyzer/RestRefreshSearchAnalyzerAction.kt
index 2055f8756..05baaa483 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/refreshanalyzer/RestRefreshSearchAnalyzerAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/refreshanalyzer/RestRefreshSearchAnalyzerAction.kt
@@ -29,8 +29,10 @@ package org.opensearch.indexmanagement.refreshanalyzer
 import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.OPEN_DISTRO_BASE_URI
 import org.opensearch.client.node.NodeClient
 import org.opensearch.common.Strings
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.PLUGINS_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.POST
 import org.opensearch.rest.action.RestToXContentListener
@@ -41,9 +43,19 @@ class RestRefreshSearchAnalyzerAction : BaseRestHandler() {
     override fun getName(): String = "refresh_search_analyzer_action"
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-                Route(POST, REFRESH_SEARCH_ANALYZER_BASE_URI),
-                Route(POST, "$REFRESH_SEARCH_ANALYZER_BASE_URI/{index}")
+            ReplacedRoute(
+                POST, REFRESH_SEARCH_ANALYZER_BASE_URI,
+                POST, LEGACY_REFRESH_SEARCH_ANALYZER_BASE_URI
+            ),
+            ReplacedRoute(
+                POST, "$REFRESH_SEARCH_ANALYZER_BASE_URI/{index}",
+                POST, "$LEGACY_REFRESH_SEARCH_ANALYZER_BASE_URI/{index}"
+            )
         )
     }
 
@@ -67,6 +79,7 @@ class RestRefreshSearchAnalyzerAction : BaseRestHandler() {
     }
 
     companion object {
-        const val REFRESH_SEARCH_ANALYZER_BASE_URI = "$OPEN_DISTRO_BASE_URI/_refresh_search_analyzers"
+        const val REFRESH_SEARCH_ANALYZER_BASE_URI = "$PLUGINS_BASE_URI/_refresh_search_analyzers"
+        const val LEGACY_REFRESH_SEARCH_ANALYZER_BASE_URI = "$OPEN_DISTRO_BASE_URI/_refresh_search_analyzers"
     }
 }
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestDeleteRollupAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestDeleteRollupAction.kt
index d72a26671..972d243bc 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestDeleteRollupAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestDeleteRollupAction.kt
@@ -32,8 +32,10 @@ import org.opensearch.indexmanagement.rollup.action.delete.DeleteRollupRequest
 import org.opensearch.indexmanagement.util.REFRESH
 import org.opensearch.action.support.WriteRequest.RefreshPolicy
 import org.opensearch.client.node.NodeClient
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ROLLUP_JOBS_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.DELETE
 import org.opensearch.rest.action.RestToXContentListener
@@ -42,8 +44,15 @@ import java.io.IOException
 class RestDeleteRollupAction : BaseRestHandler() {
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(DELETE, "$ROLLUP_JOBS_BASE_URI/{rollupID}")
+            ReplacedRoute(
+                DELETE, "$ROLLUP_JOBS_BASE_URI/{rollupID}",
+                DELETE, "$LEGACY_ROLLUP_JOBS_BASE_URI/{rollupID}"
+            )
         )
     }
 
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestExplainRollupAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestExplainRollupAction.kt
index 2a25ca4f5..b54837bd0 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestExplainRollupAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestExplainRollupAction.kt
@@ -31,8 +31,10 @@ import org.opensearch.indexmanagement.rollup.action.explain.ExplainRollupAction
 import org.opensearch.indexmanagement.rollup.action.explain.ExplainRollupRequest
 import org.opensearch.client.node.NodeClient
 import org.opensearch.common.Strings
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ROLLUP_JOBS_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.GET
 import org.opensearch.rest.action.RestToXContentListener
@@ -40,7 +42,16 @@ import org.opensearch.rest.action.RestToXContentListener
 class RestExplainRollupAction : BaseRestHandler() {
 
     override fun routes(): List<Route> {
-        return listOf(Route(GET, "$ROLLUP_JOBS_BASE_URI/{rollupID}/_explain"))
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
+        return listOf(
+            ReplacedRoute(
+                GET, "$ROLLUP_JOBS_BASE_URI/{rollupID}/_explain",
+                GET, "$LEGACY_ROLLUP_JOBS_BASE_URI/{rollupID}/_explain"
+            )
+        )
     }
 
     override fun getName(): String = "opendistro_explain_rollup_action"
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestGetRollupAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestGetRollupAction.kt
index 9ba89321b..497461c64 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestGetRollupAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestGetRollupAction.kt
@@ -37,8 +37,10 @@ import org.opensearch.indexmanagement.rollup.action.get.GetRollupsRequest.Compan
 import org.opensearch.indexmanagement.rollup.action.get.GetRollupsRequest.Companion.DEFAULT_SORT_DIRECTION
 import org.opensearch.indexmanagement.rollup.action.get.GetRollupsRequest.Companion.DEFAULT_SORT_FIELD
 import org.opensearch.client.node.NodeClient
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ROLLUP_JOBS_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.GET
 import org.opensearch.rest.RestRequest.Method.HEAD
@@ -48,10 +50,23 @@ import org.opensearch.search.fetch.subphase.FetchSourceContext
 class RestGetRollupAction : BaseRestHandler() {
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(GET, ROLLUP_JOBS_BASE_URI),
-            Route(GET, "$ROLLUP_JOBS_BASE_URI/{rollupID}"),
-            Route(HEAD, "$ROLLUP_JOBS_BASE_URI/{rollupID}")
+            ReplacedRoute(
+                GET, ROLLUP_JOBS_BASE_URI,
+                GET, LEGACY_ROLLUP_JOBS_BASE_URI
+            ),
+            ReplacedRoute(
+                GET, "$ROLLUP_JOBS_BASE_URI/{rollupID}",
+                GET, "$LEGACY_ROLLUP_JOBS_BASE_URI/{rollupID}"
+            ),
+            ReplacedRoute(
+                HEAD, "$ROLLUP_JOBS_BASE_URI/{rollupID}",
+                HEAD, "$LEGACY_ROLLUP_JOBS_BASE_URI/{rollupID}"
+            )
         )
     }
 
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestIndexRollupAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestIndexRollupAction.kt
index fec9a4355..e103ac37f 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestIndexRollupAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestIndexRollupAction.kt
@@ -39,8 +39,10 @@ import org.opensearch.action.support.WriteRequest
 import org.opensearch.client.node.NodeClient
 import org.opensearch.common.xcontent.ToXContent
 import org.opensearch.index.seqno.SequenceNumbers
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ROLLUP_JOBS_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.BaseRestHandler.RestChannelConsumer
 import org.opensearch.rest.BytesRestResponse
 import org.opensearch.rest.RestChannel
@@ -55,9 +57,19 @@ import java.time.Instant
 class RestIndexRollupAction : BaseRestHandler() {
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(PUT, ROLLUP_JOBS_BASE_URI),
-            Route(PUT, "$ROLLUP_JOBS_BASE_URI/{rollupID}")
+            ReplacedRoute(
+                PUT, ROLLUP_JOBS_BASE_URI,
+                PUT, LEGACY_ROLLUP_JOBS_BASE_URI
+            ),
+            ReplacedRoute(
+                PUT, "$ROLLUP_JOBS_BASE_URI/{rollupID}",
+                PUT, "$LEGACY_ROLLUP_JOBS_BASE_URI/{rollupID}"
+            )
         )
     }
 
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestStartRollupAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestStartRollupAction.kt
index 15266f148..fe4026dab 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestStartRollupAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestStartRollupAction.kt
@@ -31,8 +31,10 @@ import org.opensearch.indexmanagement.rollup.action.start.StartRollupAction
 import org.opensearch.indexmanagement.rollup.action.start.StartRollupRequest
 import org.opensearch.indexmanagement.rollup.model.Rollup
 import org.opensearch.client.node.NodeClient
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ROLLUP_JOBS_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.BaseRestHandler.RestChannelConsumer
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.POST
@@ -42,8 +44,15 @@ import java.io.IOException
 class RestStartRollupAction : BaseRestHandler() {
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(POST, "$ROLLUP_JOBS_BASE_URI/{rollupID}/_start")
+            ReplacedRoute(
+                POST, "$ROLLUP_JOBS_BASE_URI/{rollupID}/_start",
+                POST, "$LEGACY_ROLLUP_JOBS_BASE_URI/{rollupID}/_start"
+            )
         )
     }
 
diff --git a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestStopRollupAction.kt b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestStopRollupAction.kt
index 075affd82..fffcaebaa 100644
--- a/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestStopRollupAction.kt
+++ b/src/main/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RestStopRollupAction.kt
@@ -31,8 +31,10 @@ import org.opensearch.indexmanagement.rollup.action.stop.StopRollupAction
 import org.opensearch.indexmanagement.rollup.action.stop.StopRollupRequest
 import org.opensearch.indexmanagement.rollup.model.Rollup
 import org.opensearch.client.node.NodeClient
+import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.LEGACY_ROLLUP_JOBS_BASE_URI
 import org.opensearch.rest.BaseRestHandler
 import org.opensearch.rest.RestHandler.Route
+import org.opensearch.rest.RestHandler.ReplacedRoute
 import org.opensearch.rest.BaseRestHandler.RestChannelConsumer
 import org.opensearch.rest.RestRequest
 import org.opensearch.rest.RestRequest.Method.POST
@@ -42,8 +44,15 @@ import java.io.IOException
 class RestStopRollupAction : BaseRestHandler() {
 
     override fun routes(): List<Route> {
+        return emptyList()
+    }
+
+    override fun replacedRoutes(): List<ReplacedRoute> {
         return listOf(
-            Route(POST, "$ROLLUP_JOBS_BASE_URI/{rollupID}/_stop")
+            ReplacedRoute(
+                POST, "$ROLLUP_JOBS_BASE_URI/{rollupID}/_stop",
+                POST, "$LEGACY_ROLLUP_JOBS_BASE_URI/{rollupID}/_stop"
+            )
         )
     }
 
diff --git a/src/test/kotlin/org/opensearch/indexmanagement/IndexManagementIndicesIT.kt b/src/test/kotlin/org/opensearch/indexmanagement/IndexManagementIndicesIT.kt
index a0bb14ea4..a8e9c34a8 100644
--- a/src/test/kotlin/org/opensearch/indexmanagement/IndexManagementIndicesIT.kt
+++ b/src/test/kotlin/org/opensearch/indexmanagement/IndexManagementIndicesIT.kt
@@ -28,7 +28,17 @@ import org.opensearch.indexmanagement.indexstatemanagement.util.UPDATED_INDICES
 import org.apache.http.entity.ContentType
 import org.apache.http.entity.StringEntity
 import org.opensearch.common.settings.Settings
+import org.opensearch.common.xcontent.ToXContent
+import org.opensearch.common.xcontent.XContentFactory
+import org.opensearch.indexmanagement.indexstatemanagement.resthandler.RestAddPolicyAction
+import org.opensearch.indexmanagement.indexstatemanagement.resthandler.RestExplainAction
+import org.opensearch.indexmanagement.indexstatemanagement.resthandler.RestRemovePolicyAction
+import org.opensearch.indexmanagement.indexstatemanagement.resthandler.RestRetryFailedManagedIndexAction
+import org.opensearch.indexmanagement.opensearchapi.string
+import org.opensearch.indexmanagement.refreshanalyzer.RestRefreshSearchAnalyzerAction
+import org.opensearch.indexmanagement.rollup.randomRollup
 import org.opensearch.rest.RestRequest
+import org.opensearch.rest.RestStatus
 import org.opensearch.test.OpenSearchTestCase
 import java.util.Locale
 
@@ -147,4 +157,80 @@ class IndexManagementIndicesIT : IndexStateManagementRestTestCase() {
 
         waitFor { assertEquals(newPolicy.id, getManagedIndexConfig(index)?.changePolicy?.policyID) }
     }
+
+    fun `test ISM backward compatibility with opendistro`() {
+        val policy = randomPolicy()
+        val policyId = OpenSearchTestCase.randomAlphaOfLength(10)
+        val createIndexResponse =
+            client().makeRequest("PUT", "${IndexManagementPlugin.LEGACY_POLICY_BASE_URI}/$policyId", emptyMap(), policy.toHttpEntity())
+        assertEquals("Create policy failed", RestStatus.CREATED, createIndexResponse.restStatus())
+
+        val indexName = "bwc_index"
+        createIndex(indexName, null)
+        val addPolicyResponse = client().makeRequest(
+            RestRequest.Method.POST.toString(),
+            "${RestAddPolicyAction.LEGACY_ADD_POLICY_BASE_URI}/$indexName",
+            StringEntity("{ \"policy_id\": \"$policyId\" }", ContentType.APPLICATION_JSON)
+        )
+        assertEquals("Unexpected RestStatus", RestStatus.OK, addPolicyResponse.restStatus())
+
+        val changePolicyResponse = client().makeRequest(
+            RestRequest.Method.POST.toString(),
+            "${RestAddPolicyAction.LEGACY_ADD_POLICY_BASE_URI}/$indexName",
+            StringEntity("{ \"policy_id\": \"$policyId\" }", ContentType.APPLICATION_JSON)
+        )
+        assertEquals("Unexpected RestStatus", RestStatus.OK, changePolicyResponse.restStatus())
+
+        val retryFailedResponse = client().makeRequest(
+            RestRequest.Method.POST.toString(),
+            "${RestRetryFailedManagedIndexAction.LEGACY_RETRY_BASE_URI}/$indexName")
+        assertEquals("Unexpected RestStatus", RestStatus.OK, retryFailedResponse.restStatus())
+
+        val explainResponse = client().makeRequest(
+            RestRequest.Method.GET.toString(),
+            "${RestExplainAction.LEGACY_EXPLAIN_BASE_URI}/$indexName")
+        assertEquals("Unexpected RestStatus", RestStatus.OK, explainResponse.restStatus())
+
+        val removePolicyResponse = client().makeRequest(
+            RestRequest.Method.POST.toString(),
+            "${RestRemovePolicyAction.LEGACY_REMOVE_POLICY_BASE_URI}/$indexName")
+        assertEquals("Unexpected RestStatus", RestStatus.OK, removePolicyResponse.restStatus())
+
+        val deletePolicyResponse = client().makeRequest(
+            RestRequest.Method.DELETE.toString(),
+            "${IndexManagementPlugin.LEGACY_POLICY_BASE_URI}/$policyId")
+        assertEquals("Unexpected RestStatus", RestStatus.OK, deletePolicyResponse.restStatus())
+    }
+
+    fun `test refresh search analyzer backward compatibility with opendistro`() {
+        val indexName = "bwc_index"
+        val settings = Settings.builder().build()
+        createIndex(indexName, settings)
+        val response = client().makeRequest(RestRequest.Method.POST.toString(), "${RestRefreshSearchAnalyzerAction.LEGACY_REFRESH_SEARCH_ANALYZER_BASE_URI}/$indexName")
+        assertEquals("Unexpected RestStatus", RestStatus.OK, response.restStatus())
+    }
+
+    fun `test rollup backward compatibility with opendistro`() {
+        val rollup = randomRollup()
+        val rollupJsonString = rollup.toXContent(XContentFactory.jsonBuilder(), ToXContent.EMPTY_PARAMS).string()
+        val createRollupResponse = client().makeRequest("PUT", "${IndexManagementPlugin.LEGACY_ROLLUP_JOBS_BASE_URI}/${rollup.id}", emptyMap(), StringEntity(rollupJsonString,
+            ContentType.APPLICATION_JSON
+        ))
+        assertEquals("Create rollup failed", RestStatus.CREATED, createRollupResponse.restStatus())
+
+        val getRollupResponse = client().makeRequest("GET", "${IndexManagementPlugin.LEGACY_ROLLUP_JOBS_BASE_URI}/${rollup.id}")
+        assertEquals("Get rollup failed", RestStatus.OK, getRollupResponse.restStatus())
+
+        val explainRollupResponse = client().makeRequest("GET", "${IndexManagementPlugin.LEGACY_ROLLUP_JOBS_BASE_URI}/${rollup.id}/_explain")
+        assertEquals("Explain rollup failed", RestStatus.OK, explainRollupResponse.restStatus())
+
+        val startRollupResponse = client().makeRequest("POST", "${IndexManagementPlugin.LEGACY_ROLLUP_JOBS_BASE_URI}/${rollup.id}/_start")
+        assertEquals("Start rollup failed", RestStatus.OK, startRollupResponse.restStatus())
+
+        val stopRollupResponse = client().makeRequest("POST", "${IndexManagementPlugin.LEGACY_ROLLUP_JOBS_BASE_URI}/${rollup.id}/_stop")
+        assertEquals("Stop rollup failed", RestStatus.OK, stopRollupResponse.restStatus())
+
+        val deleteRollupResponse = client().makeRequest("DELETE", "${IndexManagementPlugin.LEGACY_ROLLUP_JOBS_BASE_URI}/${rollup.id}")
+        assertEquals("Delete rollup failed", RestStatus.OK, deleteRollupResponse.restStatus())
+    }
 }
diff --git a/src/test/kotlin/org/opensearch/indexmanagement/TestHelpers.kt b/src/test/kotlin/org/opensearch/indexmanagement/TestHelpers.kt
index 2763c077e..7e5977b90 100644
--- a/src/test/kotlin/org/opensearch/indexmanagement/TestHelpers.kt
+++ b/src/test/kotlin/org/opensearch/indexmanagement/TestHelpers.kt
@@ -26,15 +26,16 @@
 
 package org.opensearch.indexmanagement
 
-import org.opensearch.jobscheduler.spi.schedule.CronSchedule
-import org.opensearch.jobscheduler.spi.schedule.IntervalSchedule
-import org.opensearch.jobscheduler.spi.schedule.Schedule
 import org.apache.http.Header
 import org.apache.http.HttpEntity
 import org.opensearch.client.Request
 import org.opensearch.client.RequestOptions
 import org.opensearch.client.Response
 import org.opensearch.client.RestClient
+import org.opensearch.client.WarningsHandler
+import org.opensearch.jobscheduler.spi.schedule.CronSchedule
+import org.opensearch.jobscheduler.spi.schedule.IntervalSchedule
+import org.opensearch.jobscheduler.spi.schedule.Schedule
 import org.opensearch.test.rest.OpenSearchRestTestCase
 import java.time.Instant
 import java.time.temporal.ChronoUnit
@@ -76,10 +77,12 @@ fun RestClient.makeRequest(
     endpoint: String,
     params: Map<String, String> = emptyMap(),
     entity: HttpEntity? = null,
-    vararg headers: Header
+    vararg headers: Header,
+    strictDeprecationMode: Boolean = false
 ): Response {
     val request = Request(method, endpoint)
     val options = RequestOptions.DEFAULT.toBuilder()
+    options.setWarningsHandler(if (strictDeprecationMode) WarningsHandler.STRICT else WarningsHandler.PERMISSIVE)
     headers.forEach { options.addHeader(it.name, it.value) }
     request.options = options.build()
     params.forEach { request.addParameter(it.key, it.value) }
@@ -99,10 +102,12 @@ fun RestClient.makeRequest(
     method: String,
     endpoint: String,
     entity: HttpEntity? = null,
-    vararg headers: Header
+    vararg headers: Header,
+    strictDeprecationMode: Boolean = false
 ): Response {
     val request = Request(method, endpoint)
     val options = RequestOptions.DEFAULT.toBuilder()
+    options.setWarningsHandler(if (strictDeprecationMode) WarningsHandler.STRICT else WarningsHandler.PERMISSIVE)
     headers.forEach { options.addHeader(it.name, it.value) }
     request.options = options.build()
     if (entity != null) {