diff --git a/doc/changelog.md b/doc/changelog.md
index aad2c1c4..fba4236b 100644
--- a/doc/changelog.md
+++ b/doc/changelog.md
@@ -2,9 +2,9 @@
 
 # Change Log
 
-## Feb-15-2026: Version 3.25.0
+## Mar-3-2026: Version 3.26.0
 
-- Maintenance release following the change in phonopy
+- Refactoring of lattice thermal conductivity routines.
 
 ## Jan-7-2026: Version 3.24.0
 
diff --git a/doc/conf.py b/doc/conf.py
index 3404e97b..899c6359 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -58,9 +58,9 @@
 # built documents.
 #
 # The short X.Y version.
-version = "3.25"
+version = "3.26"
 # The full version, including alpha/beta/rc tags.
-release = "3.25.0"
+release = "3.26.0"
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
diff --git a/phono3py/version.py b/phono3py/version.py
index 6a24fa94..9902b4c3 100644
--- a/phono3py/version.py
+++ b/phono3py/version.py
@@ -34,4 +34,4 @@
 # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
-__version__ = "3.25.0"
+__version__ = "3.26.0"