diff --git a/leapp/cli/upgrade/__init__.py b/leapp/cli/upgrade/__init__.py
index c43f77b75..7b5cb5a63 100644
--- a/leapp/cli/upgrade/__init__.py
+++ b/leapp/cli/upgrade/__init__.py
@@ -14,7 +14,7 @@
 from leapp.repository.scan import find_and_scan_repositories
 from leapp.utils.audit import Execution, get_connection, get_checkpoints
 from leapp.utils.clicmd import command, command_opt
-from leapp.utils.output import report_errors, report_info, beautify_actor_exception
+from leapp.utils.output import report_errors, report_info, beautify_actor_exception, report_unsupported
 from leapp.utils.report import fetch_upgrade_report_messages, generate_report_file
 
 
@@ -117,6 +117,13 @@ def generate_report_files(context):
     generate_report_file(messages, context, report_txt)
 
 
+def warn_if_unsupported(configuration):
+    env = os.environ
+    if env.get('LEAPP_UNSUPPORTED', '0') == '1':
+        devel_vars = {k: env[k] for k in env if k.startswith('LEAPP_DEVEL_')}
+        report_unsupported(devel_vars, configuration["whitelist_experimental"])
+
+
 @command('upgrade', help='Upgrades the current system to the next available major version.')
 @command_opt('resume', is_flag=True, help='Continue the last execution after it was stopped (e.g. after reboot)')
 @command_opt('reboot', is_flag=True, help='Automatically performs reboot when requested.')
@@ -129,6 +136,10 @@ def upgrade(args):
 
     if args.whitelist_experimental:
         args.whitelist_experimental = list(itertools.chain(*[i.split(',') for i in args.whitelist_experimental]))
+        os.environ['LEAPP_EXPERIMENTAL'] = '1'
+    else:
+        os.environ['LEAPP_EXPERIMENTAL'] = '0'
+    os.environ['LEAPP_UNSUPPORTED'] = '0' if os.getenv('LEAPP_UNSUPPORTED', '0') == '0' else '1'
     skip_phases_until = None
     context = str(uuid.uuid4())
     configuration = {
@@ -172,6 +183,7 @@ def upgrade(args):
             msg = 'No such Actor: {}'.format(actor_name)
             logger.error(msg)
             raise CommandError(msg)
+    warn_if_unsupported(configuration)
     with beautify_actor_exception():
         answerfile_path = args.load_answerfile or get_config().get('report', 'answerfile')
         logger.info("Using answerfile at %s", answerfile_path)
@@ -195,6 +207,10 @@ def preupgrade(args):
 
     if args.whitelist_experimental:
         args.whitelist_experimental = list(itertools.chain(*[i.split(',') for i in args.whitelist_experimental]))
+        os.environ['LEAPP_EXPERIMENTAL'] = '1'
+    else:
+        os.environ['LEAPP_EXPERIMENTAL'] = '0'
+    os.environ['LEAPP_UNSUPPORTED'] = '0' if os.getenv('LEAPP_UNSUPPORTED', '0') == '0' else '1'
     context = str(uuid.uuid4())
     configuration = {
         'debug': os.getenv('LEAPP_DEBUG', '0'),
@@ -220,6 +236,7 @@ def preupgrade(args):
             msg = 'No such Actor: {}'.format(actor_name)
             logger.error(msg)
             raise CommandError(msg)
+    warn_if_unsupported(configuration)
     with beautify_actor_exception():
         until_phase = 'ReportsPhase'
         logger.info('Executing workflow until phase: %s', until_phase)
diff --git a/leapp/utils/output.py b/leapp/utils/output.py
index 64b8429bc..9ef133ec1 100644
--- a/leapp/utils/output.py
+++ b/leapp/utils/output.py
@@ -13,6 +13,7 @@ class Color(object):
     bold = "\033[1m" if sys.stdout.isatty() else ""
     red = "\033[1;31m" if sys.stdout.isatty() else ""
     green = "\033[1;32m" if sys.stdout.isatty() else ""
+    yellow = "\033[1;33m" if sys.stdout.isatty() else ""
 
 
 def pretty_block(string, color=Color.bold, width=60):
@@ -35,7 +36,7 @@ def print_error(error):
 def report_errors(errors):
     if errors:
         sys.stdout.write(pretty_block("ERRORS", color=Color.red))
-        sys.stderr.write("\n")
+        sys.stdout.write("\n")
         for error in errors:
             print_error(error)
         sys.stdout.write(pretty_block("END OF ERRORS", color=Color.red))
@@ -51,6 +52,24 @@ def report_info(path, fail=False):
         sys.stdout.write(pretty_block("END OF REPORT", color=Color.bold if fail else Color.green))
 
 
+def report_unsupported(devel_vars, experimental):
+    sys.stdout.write(pretty_block("UNSUPPORTED UPGRADE", color=Color.yellow))
+    sys.stdout.write("\nVariable LEAPP_UNSUPPORTED has been detected. Proceeding at your own risk.\n")
+
+    if devel_vars:
+        sys.stdout.write("{yellow}Development variables{reset} have been detected:\n".format(
+            yellow=Color.yellow, reset=Color.reset))
+        for key in devel_vars:
+            sys.stdout.write("- {key}={value}\n".format(key=key, value=devel_vars[key]))
+    if experimental:
+        sys.stdout.write("{yellow}Experimental actors{reset} have been detected:\n".format(
+            yellow=Color.yellow, reset=Color.reset))
+        for actor in experimental:
+            sys.stdout.write("- {actor}\n".format(actor=actor))
+    sys.stdout.write(pretty_block("UNSUPPORTED UPGRADE", color=Color.yellow))
+    sys.stdout.write("\n")
+
+
 @contextmanager
 def beautify_actor_exception():
     try: