diff --git a/subscription-service/src/main/kotlin/com/egm/stellio/subscription/service/SubscriptionService.kt b/subscription-service/src/main/kotlin/com/egm/stellio/subscription/service/SubscriptionService.kt
index 63ac66c61..00ad77bfc 100644
--- a/subscription-service/src/main/kotlin/com/egm/stellio/subscription/service/SubscriptionService.kt
+++ b/subscription-service/src/main/kotlin/com/egm/stellio/subscription/service/SubscriptionService.kt
@@ -7,6 +7,7 @@ import com.egm.stellio.shared.util.*
 import com.egm.stellio.shared.util.JsonLdUtils.JSONLD_TYPE_TERM
 import com.egm.stellio.shared.util.JsonLdUtils.NGSILD_LOCATION_PROPERTY
 import com.egm.stellio.shared.util.JsonLdUtils.NGSILD_SUBSCRIPTION_TERM
+import com.egm.stellio.shared.util.JsonLdUtils.expandJsonLdTerm
 import com.egm.stellio.subscription.config.SubscriptionProperties
 import com.egm.stellio.subscription.model.*
 import com.egm.stellio.subscription.model.GeoQ
@@ -270,7 +271,7 @@ class SubscriptionService(
         input: Map<String, Any>,
         contexts: List<String>
     ): Either<APIException, Unit> = either {
-        val subscriptionInputWithModifiedAt = input.plus("modifiedAt" to Instant.now().atZone(ZoneOffset.UTC))
+        val subscriptionInputWithModifiedAt = input.plus("modifiedAt" to ngsiLdDateTime())
 
         if (!subscriptionInputWithModifiedAt.containsKey(JSONLD_TYPE_TERM) ||
             subscriptionInputWithModifiedAt[JSONLD_TYPE_TERM]!! != NGSILD_SUBSCRIPTION_TERM
@@ -301,10 +302,16 @@ class SubscriptionService(
                     updateSubscriptionAttribute(subscriptionId, columnName, expiresAt).bind()
                 }
 
+                it.key == "watchedAttributes" -> {
+                    val value = (it.value as List<String>).map { watchedAttribute ->
+                        expandJsonLdTerm(watchedAttribute, contexts)
+                    }.toSqlValue(it.key)
+                    updateSubscriptionAttribute(subscriptionId, it.key.toSqlColumnName(), value).bind()
+                }
+
                 listOf(
                     "subscriptionName",
                     "description",
-                    "watchedAttributes",
                     "timeInterval",
                     "q",
                     "scopeQ",
diff --git a/subscription-service/src/test/kotlin/com/egm/stellio/subscription/service/SubscriptionServiceTests.kt b/subscription-service/src/test/kotlin/com/egm/stellio/subscription/service/SubscriptionServiceTests.kt
index cb91f5d03..24c197ff3 100644
--- a/subscription-service/src/test/kotlin/com/egm/stellio/subscription/service/SubscriptionServiceTests.kt
+++ b/subscription-service/src/test/kotlin/com/egm/stellio/subscription/service/SubscriptionServiceTests.kt
@@ -770,13 +770,13 @@ class SubscriptionServiceTests : WithTimescaleContainer {
     }
 
     @Test
-    fun `it should update a subscription watched attributes`() = runTest {
+    fun `it should update and expand watched attributes of a subscription`() = runTest {
         val parsedInput = mapOf(
             "type" to NGSILD_SUBSCRIPTION_TERM,
-            "watchedAttributes" to arrayListOf(INCOMING_PROPERTY, TEMPERATURE_PROPERTY)
+            "watchedAttributes" to arrayListOf(INCOMING_COMPACT_PROPERTY, TEMPERATURE_COMPACT_PROPERTY)
         )
 
-        subscriptionService.update(subscription5Id, parsedInput, listOf(APIC_COMPOUND_CONTEXT))
+        subscriptionService.update(subscription5Id, parsedInput, listOf(APIC_COMPOUND_CONTEXT)).shouldSucceed()
 
         val subscription = subscriptionService.getById(subscription5Id)