diff --git a/build/builder.py b/build/builder.py
index 4a8dd7a1..a861bff8 100644
--- a/build/builder.py
+++ b/build/builder.py
@@ -20,32 +20,24 @@ def build(ctx, config, version):
 
     \b
     Runs the following in order:
-        wq init        (if using wq optimize)
+        wq init        (if using r.js)
         wq setversion
         wq collectjson (if configured)
         wq scss        (if configured)
         wq mustache    (if configured)
-
-    \b
-    Followed by either:
-        wq optimize + wq babel + wq appcache
-    Or:
-        npm build
+        npm build      (if using npm)
+        wq optimize    (if using r.js)
+        wq babel       (if configured & using r.js)
+        wq appcache    (if configured & using r.js)
     """
 
     has_package_json = os.path.exists(
         os.path.join(os.path.dirname(config.filename), 'package.json')
     )
-    if has_package_json:
-        if 'optimize' in config:
-            raise click.UsageError(
-                "optimize section is not used for npm build"
-            )
-    else:
-        if 'optimize' not in config:
-            raise click.UsageError(
-                "optimize section not found in %s" % config.filename
-            )
+    if has_package_json and 'optimize' in config:
+        raise click.UsageError(
+            "optimize section is not used for npm build"
+        )
 
     def run(command, **kwargs):
         confs = config.get(command.name, {})
@@ -55,7 +47,7 @@ def run(command, **kwargs):
             conf.update(kwargs)
             ctx.invoke(command, **conf)
 
-    if not has_package_json:
+    if 'optimize' in config:
         run(init)
 
     # Save version information
@@ -70,7 +62,7 @@ def run(command, **kwargs):
             ['npm', 'build'],
             cwd=os.path.abspath(os.path.dirname(config.filename))
         )
-    else:
+    elif 'optimize' in config:
         # Compile Javascript / CSS (using r.js)
         ctx.invoke(optimize)
 
diff --git a/build/setversion.py b/build/setversion.py
index e65304e5..3b24a457 100644
--- a/build/setversion.py
+++ b/build/setversion.py
@@ -1,6 +1,7 @@
 import os
 from wq.core import wq
 import click
+import re
 
 
 @wq.command()
@@ -9,6 +10,8 @@
     help="Name of text file (default is version.txt)"
 )
 @click.option('--jsout', help="Name of an AMD module (e.g. myapp/version.js)")
+@click.option('--esm', help="Name of an ESM module (e.g. myapp/version.js)")
+@click.option('--package', help="Path to package.json")
 @click.argument('version')
 def setversion(**conf):
     """
@@ -27,16 +30,29 @@ def setversion(**conf):
         vtxt.write(version)
         vtxt.close()
 
-    if conf['jsout']:
+    if conf['esm'] or conf['jsout']:
         # Update version.js
-        vjs = open(conf['jsout'], 'w')
-        vjs.write(VERSIONJS_TMPL % version)
-        vjs.close()
-        click.echo('%s: %s' % (conf['jsout'], version))
+        if conf['esm']:
+            js_file = conf['esm']
+            js_tmpl = """export default "%s";"""
+        else:
+            js_file = conf['jsout']
+            js_tmpl = """define(function(){return "%s";});"""
+        with open(js_file, 'w') as f:
+            f.write(js_tmpl % version)
+        click.echo('%s: %s' % (js_file, version))
     else:
         click.echo('Application version: %s' % version)
 
-    return version
-
+    if conf['package']:
+        with open(conf['package']) as f:
+            content = f.read()
+        content = re.sub(
+            '"version": "[^"]+"',
+            '"version": "%s"' % version,
+            content
+        )
+        with open(conf['package'], 'w') as f:
+            f.write(content)
 
-VERSIONJS_TMPL = """define(function(){return "%s";});"""
+    return version