diff --git a/internal/builder/config.go b/internal/builder/config.go
index fa253e8822a3..b771871dd3d0 100644
--- a/internal/builder/config.go
+++ b/internal/builder/config.go
@@ -32,6 +32,9 @@ const defaultOtelColVersion = "0.36.0"
 // ErrInvalidGoMod indicates an invalid gomod
 var ErrInvalidGoMod = errors.New("invalid gomod specification for module")
 
+// ErrDeprecatedCore indicates deprecated core
+var ErrDeprecatedCore = errors.New("mod.Core has deprecated, you should not be used anymore and required to be set mod.GoMod instead")
+
 // Config holds the builder's configuration
 type Config struct {
 	Logger          logr.Logger
@@ -64,7 +67,8 @@ type Module struct {
 	Import string `mapstructure:"import"` // if not specified, this is the path part of the go mods
 	GoMod  string `mapstructure:"gomod"`  // a gomod-compatible spec for the module
 	Path   string `mapstructure:"path"`   // an optional path to the local version of this module
-	Core   bool   `mapstructure:"core"`   // whether this module comes from core, meaning that no further dependencies will be added
+	Core   *bool  `mapstructure:"core"`   // whether this module comes from core. For this property isn't referred from anywhere, it might be removed. please see #15.
+
 }
 
 // DefaultConfig creates a new config, with default values
@@ -134,7 +138,10 @@ func (c *Config) ParseModules() error {
 func parseModules(mods []Module) ([]Module, error) {
 	var parsedModules []Module
 	for _, mod := range mods {
-		if mod.GoMod == "" && !mod.Core {
+		if mod.Core != nil {
+			return mods, ErrDeprecatedCore
+		}
+		if mod.GoMod == "" {
 			return mods, fmt.Errorf("%w, module: %q", ErrInvalidGoMod, mod.GoMod)
 		}
 
diff --git a/internal/builder/config_test.go b/internal/builder/config_test.go
index 08fab22c821b..0b3cd9ba7ef3 100644
--- a/internal/builder/config_test.go
+++ b/internal/builder/config_test.go
@@ -65,10 +65,17 @@ func TestRelativePath(t *testing.T) {
 func TestModuleFromCore(t *testing.T) {
 	// prepare
 	cfg := Config{
-		Extensions: []Module{{
-			Core:   true,
-			Import: "go.opentelemetry.io/collector/receiver/jaegerreceiver",
-		}},
+		Extensions: []Module{ // see issue-12
+			{
+				Import: "go.opentelemetry.io/collector/receiver/jaegerreceiver",
+				GoMod:  "go.opentelemetry.io/collector v0.36.0",
+			},
+			{
+				Import: "go.opentelemetry.io/collector/receiver/jaegerreceiver",
+				GoMod:  "go.opentelemetry.io/collector v0.36.0",
+				Core:   nil,
+			},
+		},
 	}
 
 	// test
@@ -77,7 +84,30 @@ func TestModuleFromCore(t *testing.T) {
 
 	// verify
 	assert.True(t, strings.HasPrefix(cfg.Extensions[0].Name, "jaegerreceiver"))
-	assert.Empty(t, cfg.Extensions[0].GoMod)
+}
+
+func TestDeprecatedCore(t *testing.T) {
+	// prepare
+	coreTrue := true
+	coreFalse := false
+	cfg := Config{
+		Extensions: []Module{
+			{
+				Import: "go.opentelemetry.io/collector/receiver/jaegerreceiver",
+				Core:   &coreTrue,
+			},
+			{
+				Import: "go.opentelemetry.io/collector/receiver/jaegerreceiver",
+				Core:   &coreFalse,
+			},
+		},
+	}
+
+	// test
+	err := cfg.ParseModules()
+
+	// verify
+	assert.True(t, errors.Is(err, ErrDeprecatedCore))
 }
 
 func TestInvalidModule(t *testing.T) {
diff --git a/test/nocore.builder.yaml b/test/nocore.builder.yaml
index 49dec4b20020..8cee42670dcb 100644
--- a/test/nocore.builder.yaml
+++ b/test/nocore.builder.yaml
@@ -5,10 +5,10 @@ dist:
 
 receivers:
   - import: go.opentelemetry.io/collector/receiver/otlpreceiver
-    core: true
+    gomod: go.opentelemetry.io/collector v0.36.0
 exporters:
   - import: go.opentelemetry.io/collector/exporter/loggingexporter
-    core: true
+    gomod: go.opentelemetry.io/collector v0.36.0
 extensions:
   - import: go.opentelemetry.io/collector/extension/zpagesextension
-    core: true
+    gomod: go.opentelemetry.io/collector v0.36.0