diff --git a/docs/conf.py b/docs/conf.py
index 628f20d2f..98a753201 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -24,7 +24,7 @@
 author = "Lhotse development team"
 
 # The full version, including alpha/beta/rc tags
-release = "1.8.0"
+release = "1.9.0.dev"
 
 # -- General configuration ---------------------------------------------------
 
diff --git a/lhotse/__init__.py b/lhotse/__init__.py
index c9f7ae96a..b879f6e9b 100644
--- a/lhotse/__init__.py
+++ b/lhotse/__init__.py
@@ -34,7 +34,7 @@
     # NOTE: REMEMBER TO UPDATE THE ACTUAL VERSION IN setup.py WHEN RELEASING #
     # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! #
     # Use a default placeholder when the version is unavailable...
-    __version__ = "1.8.0+missing.version.file"
+    __version__ = "1.9.0.dev+missing.version.file"
 
 from . import augmentation, dataset, features, recipes
 
diff --git a/setup.py b/setup.py
index ebb06e6fe..6202f5fc5 100644
--- a/setup.py
+++ b/setup.py
@@ -53,9 +53,9 @@
 # NOTE: REMEMBER TO UPDATE THE FALLBACK VERSION IN lhotse/__init__.py WHEN RELEASING #
 # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! #
 MAJOR_VERSION = 1
-MINOR_VERSION = 8
+MINOR_VERSION = 9
 PATCH_VERSION = 0
-IS_DEV_VERSION = False  # False = public release, True = otherwise
+IS_DEV_VERSION = True  # False = public release, True = otherwise
 
 
 if sys.version_info < (3,):