diff --git a/checker/rule.go b/checker/rule.go
index f336ba5..d201dd6 100644
--- a/checker/rule.go
+++ b/checker/rule.go
@@ -44,14 +44,14 @@ func (r *zonemasterRule) ValidateOptions(opts sdk.CheckerOptions) error {
 	return nil
 }
 
-func (r *zonemasterRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, opts sdk.CheckerOptions) sdk.CheckState {
+func (r *zonemasterRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, opts sdk.CheckerOptions) []sdk.CheckState {
 	var data ZonemasterData
 	if err := obs.Get(ctx, ObservationKeyZonemaster, &data); err != nil {
-		return sdk.CheckState{
+		return []sdk.CheckState{{
 			Status:  sdk.StatusError,
 			Message: fmt.Sprintf("Failed to get Zonemaster data: %v", err),
 			Code:    "zonemaster_error",
-		}
+		}}
 	}
 
 	var errorCount, warningCount int
@@ -86,27 +86,27 @@ func (r *zonemasterRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter
 			}
 			statusLine += ": " + strings.Join(criticalMsgs[:n], "; ")
 		}
-		return sdk.CheckState{
+		return []sdk.CheckState{{
 			Status:  sdk.StatusCrit,
 			Message: statusLine,
 			Code:    "zonemaster_errors",
 			Meta:    meta,
-		}
+		}}
 	}
 
 	if warningCount > 0 {
-		return sdk.CheckState{
+		return []sdk.CheckState{{
 			Status:  sdk.StatusWarn,
 			Message: fmt.Sprintf("%d warning(s) found", warningCount),
 			Code:    "zonemaster_warnings",
 			Meta:    meta,
-		}
+		}}
 	}
 
-	return sdk.CheckState{
+	return []sdk.CheckState{{
 		Status:  sdk.StatusOK,
 		Message: fmt.Sprintf("All checks passed (%d checks)", len(data.Results)),
 		Code:    "zonemaster_ok",
 		Meta:    meta,
-	}
+	}}
 }
diff --git a/go.mod b/go.mod
index dd1b138..ffeb7b4 100644
--- a/go.mod
+++ b/go.mod
@@ -2,4 +2,4 @@ module git.happydns.org/checker-zonemaster
 
 go 1.25.0
 
-require git.happydns.org/checker-sdk-go v0.0.1
+require git.happydns.org/checker-sdk-go v1.2.0
diff --git a/go.sum b/go.sum
index 5282be1..272600a 100644
--- a/go.sum
+++ b/go.sum
@@ -1,2 +1,2 @@
-git.happydns.org/checker-sdk-go v0.0.1 h1:4RxCJr73HWKxjOyU/6NJMO8lXJmH0gMLA68EzTqLbQI=
-git.happydns.org/checker-sdk-go v0.0.1/go.mod h1:aNAcfYFfbhvH9kJhE0Njp5GX0dQbxdRB0rJ0KvSC5nI=
+git.happydns.org/checker-sdk-go v1.2.0 h1:v4MpKAz0W3PwP+bxx3pya8w893sVH5xTD1of1cc0TV8=
+git.happydns.org/checker-sdk-go v1.2.0/go.mod h1:aNAcfYFfbhvH9kJhE0Njp5GX0dQbxdRB0rJ0KvSC5nI=