diff --git a/datamodel/spec_info.go b/datamodel/spec_info.go
index bb238ac..cb39e68 100644
--- a/datamodel/spec_info.go
+++ b/datamodel/spec_info.go
@@ -173,7 +173,7 @@ func ExtractSpecInfo(spec []byte) (*SpecInfo, error) {
 	if specVersion.SpecType == "" {
 		// parse JSON
 		parseJSON(spec, specVersion, &parsedSpec)
-		specVersion.Error = errors.New("spec type not supported by vacuum, sorry")
+		specVersion.Error = errors.New("spec type not supported by libopenapi, sorry")
 		return specVersion, specVersion.Error
 	}
 
diff --git a/document.go b/document.go
index 5a7a5e7..24ab95f 100644
--- a/document.go
+++ b/document.go
@@ -186,7 +186,12 @@ func CompareDocuments(original, updated Document) (*model.DocumentChanges, []err
 		if len(errs) > 0 {
 			errors = errs
 		}
-		return what_changed.CompareOpenAPIDocuments(v3ModelLeft.Model.GoLow(), v3ModelRight.Model.GoLow()), errors
+		if v3ModelLeft != nil && v3ModelRight != nil {
+			return what_changed.CompareOpenAPIDocuments(v3ModelLeft.Model.GoLow(), v3ModelRight.Model.GoLow()), errors
+		} else {
+			return nil, errs
+		}
+
 	}
 	if original.GetSpecInfo().SpecType == utils.OpenApi2 && updated.GetSpecInfo().SpecType == utils.OpenApi2 {
 		v2ModelLeft, errs := original.BuildV2Model()
@@ -197,7 +202,11 @@ func CompareDocuments(original, updated Document) (*model.DocumentChanges, []err
 		if len(errs) > 0 {
 			errors = errs
 		}
-		return what_changed.CompareSwaggerDocuments(v2ModelLeft.Model.GoLow(), v2ModelRight.Model.GoLow()), errors
+		if v2ModelLeft != nil && v2ModelRight != nil {
+			return what_changed.CompareSwaggerDocuments(v2ModelLeft.Model.GoLow(), v2ModelRight.Model.GoLow()), errors
+		} else {
+			return nil, errs
+		}
 	}
 	return nil, nil
 }
diff --git a/utils/utils.go b/utils/utils.go
index 7fc0dce..15a5f91 100644
--- a/utils/utils.go
+++ b/utils/utils.go
@@ -312,7 +312,7 @@ var BinaryLabel = "binary"
 var ArrayLabel = "array"
 var BooleanLabel = "boolean"
 var SchemaSource = "https://json-schema.org/draft/2020-12/schema"
-var SchemaId = "https://quobix.com/api/vacuum"
+var SchemaId = "https://pb33f.io/openapi-changes/schema"
 
 func MakeTagReadable(node *yaml.Node) string {
 	switch node.Tag {