diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index ef8fe9c7..362ca5f8 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,9 +1,9 @@
 [bumpversion]
-current_version = 2.6.0
+current_version = 2.6.3
 commit = True
 tag = False
 
-[bumpversion:file:vonage/__init__.py]
+[bumpversion:file:src/vonage/__init__.py]
 
 [bumpversion:file:setup.py]
 
diff --git a/CHANGES.md b/CHANGES.md
index ecdffe41..c343e509 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,10 +1,10 @@
-# 2.6.0
+# 2.6.x
 
 - Dropped support for Python 3.6 and below
 - Now supporting currently supported stable versions of Python, i.e. Python 3.7-3.10
 - Internal refactoring and enhancements
 
-# 2.5.x
+# 2.5.5
 
 - Support for Independent SMS, Voice and Verify APIs with tests as well as current client methods
 - Getters/Setters to extract/rewrite custom attributes
diff --git a/Makefile b/Makefile
index a6533e10..5bad49a6 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-.PHONY: clean test dist coverage install requirements release
+.PHONY: clean test build coverage install requirements release
 
 clean:
 	rm -rf dist build
@@ -10,11 +10,11 @@ coverage:
 test:
 	pytest -v
 
-dist:
-	python setup.py sdist --formats zip,gztar bdist_wheel
+build:
+	python -m build
 
 release:
-	twine upload dist/*
+	python -m twine upload dist/*
 
 install: requirements
 
diff --git a/docs/conf.py b/docs/conf.py
index d2b3da73..1a2ae070 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -66,9 +66,9 @@
 # built documents.
 #
 # The short X.Y version.
-version = "2.6.0"
+version = "2.6.3"
 # The full version, including alpha/beta/rc tags.
-release = "2.6.0"
+release = "2.6.3"
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -143,7 +143,7 @@
 # The name for this set of Sphinx documents.
 # "<project> v<release> documentation" by default.
 #
-# html_title = u'Vonage v2.6.0'
+# html_title = u'Vonage v2.6.3'
 
 # A shorter title for the navigation bar.  Default is the same as html_title.
 #
diff --git a/setup.cfg b/setup.cfg
index 37ff610d..45444f0b 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -9,7 +9,7 @@ max-line-length=120
 [coverage:run]
 # TODO: Change this to True:
 branch=False
-source= vonage
+source=src
 
 [coverage:paths]
 source =
diff --git a/setup.py b/setup.py
index 35c4b700..63bed902 100644
--- a/setup.py
+++ b/setup.py
@@ -11,7 +11,7 @@
 
 setup(
     name="vonage",
-    version="2.6.0",
+    version="2.6.3",
     description="Vonage Server SDK for Python",
     long_description=long_description,
     long_description_content_type="text/markdown",
@@ -19,8 +19,8 @@
     author="Vonage",
     author_email="devrel@vonage.com",
     license="Apache",
-    packages=find_packages(where="vonage"),
-    package_dir={"": "."},
+    packages=find_packages(where="src"),
+    package_dir={"": "src"},
     platforms=["any"],
     install_requires=[
         "requests>=2.4.2",
diff --git a/vonage/__init__.py b/src/vonage/__init__.py
similarity index 82%
rename from vonage/__init__.py
rename to src/vonage/__init__.py
index b6d6fa14..b041a7e2 100644
--- a/vonage/__init__.py
+++ b/src/vonage/__init__.py
@@ -4,4 +4,4 @@
 from .sms import *
 from .verify import *
 
-__version__ = "2.6.0"
+__version__ = "2.6.3"
diff --git a/vonage/_internal.py b/src/vonage/_internal.py
similarity index 100%
rename from vonage/_internal.py
rename to src/vonage/_internal.py
diff --git a/vonage/client.py b/src/vonage/client.py
similarity index 99%
rename from vonage/client.py
rename to src/vonage/client.py
index f4807559..09ecde16 100644
--- a/vonage/client.py
+++ b/src/vonage/client.py
@@ -110,7 +110,7 @@ def __init__(
         if app_name and app_version:
             user_agent += f" {app_name}/{app_version}"
 
-        self.headers = {"User-Agent": user_agent, "Content-Type": "application/json"}
+        self.headers = {"User-Agent": user_agent, "Accept": "application/json"}
 
         self.auth_params = {}
 
diff --git a/vonage/errors.py b/src/vonage/errors.py
similarity index 100%
rename from vonage/errors.py
rename to src/vonage/errors.py
diff --git a/vonage/sms.py b/src/vonage/sms.py
similarity index 100%
rename from vonage/sms.py
rename to src/vonage/sms.py
diff --git a/vonage/verify.py b/src/vonage/verify.py
similarity index 100%
rename from vonage/verify.py
rename to src/vonage/verify.py
diff --git a/vonage/voice.py b/src/vonage/voice.py
similarity index 100%
rename from vonage/voice.py
rename to src/vonage/voice.py