diff --git a/Makefile b/Makefile
index edea9b2..2a34ab2 100644
--- a/Makefile
+++ b/Makefile
@@ -2,22 +2,22 @@
 # Makefile
 
 # Define the sample images to build (assuming each subdirectory in samples is an app)
-SAMPLE_IMAGES := $(shell find samples -maxdepth 1 -type d -not -path "samples" -printf "%P ")
+SAMPLE_IMAGES ?= $(shell find samples -maxdepth 1 -type d -not -path "samples" -printf "%P ")
 
 # Buildpacks directory (assuming each subdirectory contains a buildpack)
-BUILDPACKS := $(shell find buildpacks -maxdepth 1 -type d -not -path "buildpacks" -printf "%P ")
+BUILDPACKS ?= $(shell find buildpacks -maxdepth 1 -type d -not -path "buildpacks" -printf "%P ")
 
 # Buildpacks directory (assuming each subdirectory contains a buildpack)
-EXTENSIONS := $(shell find extensions -maxdepth 1 -type d -not -path "extensions" -printf "%P ")
+EXTENSIONS ?= $(shell find extensions -maxdepth 1 -type d -not -path "extensions" -printf "%P ")
 
 # Builders directory (assuming each subdirectory contains a builder definition)
-BUILDERS := $(shell find builders -maxdepth 1 -type d -not -path "builders" -printf "%P ")
+BUILDERS ?= $(shell find builders -maxdepth 1 -type d -not -path "builders" -printf "%P ")
 
 # Define the builder image to use
 BUILDER_IMAGE ?= $(word 1, $(BUILDERS))
 
 # Define the allowed frontends
-FRONTENDS := jupyterlab vscodium
+FRONTENDS ?= jupyterlab vscodium
 
 # Define the frontend image to use
 FRONTEND ?= $(word 1, $(FRONTENDS))
@@ -29,28 +29,28 @@ SAMPLE_IMAGE ?= $(word 1, $(SAMPLE_IMAGES))
 all: buildpacks extensions builders samples
 
 buildpacks:
-	@echo "Building buildpacks..."
+	@echo "Building buildpacks $(BUILDPACKS)..."
 	@for bp in $(BUILDPACKS); do \
 		echo "  Building buildpack: $$bp"; \
 		pack buildpack package $$bp --config buildpacks/$$bp/package.toml --target "linux/amd64"; \
 	done
 
 extensions:
-	@echo "Building extensions..."
+	@echo "Building extensions $(EXTENSIONS)..."
 	@for extension in $(EXTENSIONS); do \
 		echo "  Building extension: $$extension"; \
 		pack extension package $$extension --config extensions/$$extension/package.toml; \
 	done
 
 builders:
-	@echo "Building builders..."
+	@echo "Building builders $(BUILDERS)..."
 	@for builder in $(BUILDERS); do \
 		echo "  Building builder: $$builder"; \
 		pack builder create $$builder --config builders/$$builder/builder.toml --target "linux/amd64"; \
 	done
 
 samples:
-	@echo "Building sample images..."
+	@echo "Building sample images $(SAMPLE_IMAGES)..."
 	@for image in $(SAMPLE_IMAGES); do \
 		echo "  Building image: $$image with $(BUILDER_IMAGE)"; \
 		pack build $$image-$(FRONTEND) --path samples/$$image --env BP_REQUIRES=$(FRONTEND) --builder $(BUILDER_IMAGE) --platform "linux"; \
diff --git a/builders/selector/builder.toml b/builders/selector/builder.toml
index caec52a..60cd97b 100644
--- a/builders/selector/builder.toml
+++ b/builders/selector/builder.toml
@@ -2,39 +2,35 @@ description = "Ubuntu 22.04 Jammy Jellyfish full image with buildpacks for Apach
 
 [[buildpacks]]
   uri = "docker://ghcr.io/swissdatasciencecenter/vscodium-buildpack/vscodium:0.2"
-  version = "0.2.0"
 
 [[buildpacks]]
   uri = "../../buildpacks/kernel-installer"
-  version = "0.0.1"
+  id = "renku/kernel-installer"
 
 [[buildpacks]]
   uri = "../../buildpacks/frontend-selector"
-  version = "0.0.1"
 
 [[buildpacks]]
   uri = "../../buildpacks/jupyterlab"
-  version = "0.0.1"
 
 [[buildpacks]]
   uri = "../../buildpacks/frontends"
-  version = "0.0.1"
+  id = "renku/frontends"
 
 [[buildpacks]]
   uri = "docker://gcr.io/paketo-buildpacks/go:4.13.11"
-  version = "4.13.11"
+  id = "paketo-buildpacks/go"
 
 [[buildpacks]]
   uri = "docker://gcr.io/paketo-buildpacks/nodejs:7.4.0"
-  version = "7.4.0"
+  id = "paketo-buildpacks/nodejs"
 
 [[buildpacks]]
   uri = "docker://gcr.io/paketo-buildpacks/python:2.24.3"
-  version = "2.24.3"
+  id = "paketo-buildpacks/python"
 
 [[extensions]]
   id = "renku/renku"
-  version = "0.0.1"
   uri = "../../extensions/renku"
 
 [lifecycle]
@@ -44,46 +40,36 @@ description = "Ubuntu 22.04 Jammy Jellyfish full image with buildpacks for Apach
 
   [[order.group]]
     id = "renku/frontends"
-    version = "0.0.1"
   [[order.group]]
     id = "paketo-buildpacks/go"
-    version = "4.13.11"
   [[order.group]]
     id = "renku/kernel-installer"
-    version = "0.0.1"
     optional = true
 
 [[order]]
 
   [[order.group]]
     id = "renku/frontends"
-    version = "0.0.1"
   [[order.group]]
     id = "paketo-buildpacks/python"
-    version = "2.24.3"
   [[order.group]]
     id = "renku/kernel-installer"
-    version = "0.0.1"
     optional = true
 
 [[order]]
 
   [[order.group]]
     id = "renku/frontends"
-    version = "0.0.1"
   [[order.group]]
     id = "paketo-buildpacks/nodejs"
-    version = "7.4.0"
   [[order.group]]
     id = "renku/kernel-installer"
-    version = "0.0.1"
     optional = true
 
 [[order-extensions]]
 
   [[order-extensions.group]]
     id = "renku/renku"
-    version = "0.0.1"
 
 [stack]
   build-image = "docker.io/paketobuildpacks/build-jammy-full:0.1.76"