diff --git a/CHANGELOG.md b/CHANGELOG.md
index 20b2f7a..df8f678 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,6 @@
 # Change Log
+* 4.0.4:
+    * Improvement: Replace setup.py by pyproject.toml
 * 4.0.2:
     * Bug Fix: arg `src` in `verbose_ping` should be `src_addr`. ( #57 )
 * 4.0.1:
diff --git a/ping3/__init__.py b/ping3/__init__.py
index f1123c3..ad9f1f2 100644
--- a/ping3/__init__.py
+++ b/ping3/__init__.py
@@ -15,7 +15,7 @@
 from . import errors
 from .enums import ICMP_DEFAULT_CODE, IcmpType, IcmpTimeExceededCode, IcmpDestinationUnreachableCode
 
-__version__ = "4.0.3"
+__version__ = "4.0.4"
 DEBUG = False  # DEBUG: Show debug info for developers. (default False)
 EXCEPTIONS = False  # EXCEPTIONS: Raise exception when delay is not available.
 LOGGER = None  # LOGGER: Record logs into console or file.