diff --git a/fixcore/fixcore/__main__.py b/fixcore/fixcore/__main__.py
index 14a583ede9..d74ad71b00 100644
--- a/fixcore/fixcore/__main__.py
+++ b/fixcore/fixcore/__main__.py
@@ -67,6 +67,7 @@
 from fixcore.web.certificate_handler import CertificateHandlerWithCA, CertificateHandlerNoCA
 from fixcore.worker_task_queue import WorkerTaskQueue
 from fixlib.asynchronous.web import runner
+from fixlib.utils import ensure_bw_compat
 
 log = logging.getLogger("fixcore")
 
@@ -75,6 +76,7 @@ def main() -> None:
     """
     Application entrypoint - no arguments are allowed.
     """
+    ensure_bw_compat()
     try:
         run(sys.argv[1:])
         log.info("Process finished.")
diff --git a/fixlib/fixlib/utils.py b/fixlib/fixlib/utils.py
index cff6161724..466dba7388 100644
--- a/fixlib/fixlib/utils.py
+++ b/fixlib/fixlib/utils.py
@@ -573,3 +573,14 @@ def freeze(elem: JsonElement) -> Any:
         return frozendict({k: freeze(v) for k, v in elem.items()})
     else:
         return elem
+
+
+def ensure_bw_compat() -> None:
+    for i, arg in enumerate(sys.argv):
+        if arg.startswith("--resoto"):
+            sys.argv[i] = "--fix" + arg[len("--resoto") :]
+
+    old_env_vars = [key for key in os.environ if key.startswith("RESOTO")]
+    for old_env_var in old_env_vars:
+        new_env_var = "FIX" + old_env_var[len("RESOTO") :]
+        os.environ[new_env_var] = os.environ.pop(old_env_var)
diff --git a/fixmetrics/fixmetrics/__main__.py b/fixmetrics/fixmetrics/__main__.py
index 97c1866684..ac3eeddde2 100644
--- a/fixmetrics/fixmetrics/__main__.py
+++ b/fixmetrics/fixmetrics/__main__.py
@@ -29,6 +29,7 @@
 from threading import Event
 from typing import Optional
 from fixlib.args import ArgumentParser
+from fixlib.utils import ensure_bw_compat
 
 
 shutdown_event = Event()
@@ -45,6 +46,7 @@ def shutdown(event: FixEvent) -> None:
 
 
 def main() -> None:
+    ensure_bw_compat()
     setup_logger("fixmetrics")
     fixlib.proc.parent_pid = os.getpid()
 
diff --git a/fixshell/fixshell/__main__.py b/fixshell/fixshell/__main__.py
index ca517507ac..6b48558c7e 100644
--- a/fixshell/fixshell/__main__.py
+++ b/fixshell/fixshell/__main__.py
@@ -20,6 +20,7 @@
 from fixshell import authorized_client
 from fixshell.promptsession import PromptSession, core_metadata, FixHistory
 from fixshell.shell import Shell, ShutdownShellError
+from fixlib.utils import ensure_bw_compat
 
 
 async def main_async() -> None:
@@ -218,6 +219,7 @@ def header_value(s: str) -> Tuple[str, str]:
 
 
 def main() -> None:
+    ensure_bw_compat()
     asyncio.run(main_async())
     fixlib.proc.kill_children(SIGTERM, ensure_death=True)
     log.debug("Shutdown complete")
diff --git a/fixworker/fixworker/__main__.py b/fixworker/fixworker/__main__.py
index ea1b9d1b79..b6e2320ef7 100644
--- a/fixworker/fixworker/__main__.py
+++ b/fixworker/fixworker/__main__.py
@@ -34,6 +34,7 @@
 from fixworker.fixcore import FixCore
 from fixworker.tag import core_tag_tasks_processor
 from fixworker.exceptions import DuplicateMessageError
+from fixlib.utils import ensure_bw_compat
 
 # This will be used in main() and shutdown()
 shutdown_event = threading.Event()
@@ -42,6 +43,7 @@
 
 
 def main() -> None:
+    ensure_bw_compat()
     setup_logger("fixworker")
     # Try to run in a new process group and
     # ignore if not possible for whatever reason