diff --git a/.github/ISSUE_TEMPLATE.md b/.github/ISSUE_TEMPLATE.md
index c1b8072bb3..e90d0a12f7 100644
--- a/.github/ISSUE_TEMPLATE.md
+++ b/.github/ISSUE_TEMPLATE.md
@@ -24,4 +24,4 @@ Describe what you expect the output to be. Knowing the correct behavior is also
 Provide any additional information here.
 
 #### Current Version:
-v2.33.0
+v2.34.0
diff --git a/RELEASE-NOTES.txt b/RELEASE-NOTES.txt
index 3823d08675..fee4c304fd 100644
--- a/RELEASE-NOTES.txt
+++ b/RELEASE-NOTES.txt
@@ -5,6 +5,19 @@ Note: these are the release notes for the stan-dev/stan repository.
 Further changes may arise at the interface level (stan-dev/{rstan,
 pystan, cmdstan}) and math library level (stan-dev/math).
 
+v2.34.0 (16 January 2024)
+======================================================================
+
+ - Resolved an issue in Pathfinder's multithreading which lead to non-reproducible results (#3239)
+ - Improved the human-readability of the output of the JSON writer class (#3227)
+ - Resolved various compiler warnings (#3228, #3234)
+ - Added hooks to adaptive sampler methods to write adapted metric to JSON file. (#3230, #3248)
+ - Changed bfgs and lbfgs's error messaging behavior so that the message is not split between stderr and stdout but is entirely sent to stderr. (#3238)
+ - Fixed a bug in the stan opencl assign tests (#3219)
+ - Updated PSIS to not add back the max and return the unnormalized resample ratios for stability (#3243)
+ - Fixed an issue where trying to compute the potential scale reduction factor on an empty set of draws would lead to a crash (#3246)
+ - Added flags to the Pathfinder service functions for turning off resampling and the calculation of the lp for the approximate draws. (#3249)
+
 v2.33.0 (5 September 2023)
 ======================================================================
 
diff --git a/src/doxygen/doxygen.cfg b/src/doxygen/doxygen.cfg
index edd536ec19..a92cbfef95 100644
--- a/src/doxygen/doxygen.cfg
+++ b/src/doxygen/doxygen.cfg
@@ -38,7 +38,7 @@ PROJECT_NAME           = "Stan"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 2.33.0
+PROJECT_NUMBER         = 2.34.0
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a
diff --git a/src/stan/version.hpp b/src/stan/version.hpp
index f383b43160..0ad4ad6176 100644
--- a/src/stan/version.hpp
+++ b/src/stan/version.hpp
@@ -12,7 +12,7 @@
 #endif
 
 #define STAN_MAJOR 2
-#define STAN_MINOR 33
+#define STAN_MINOR 34
 #define STAN_PATCH 0
 
 namespace stan {
diff --git a/src/test/unit/version_test.cpp b/src/test/unit/version_test.cpp
index 76779cfdaf..78a0f79c71 100644
--- a/src/test/unit/version_test.cpp
+++ b/src/test/unit/version_test.cpp
@@ -3,12 +3,12 @@
 
 TEST(Stan, macro) {
   EXPECT_EQ(2, STAN_MAJOR);
-  EXPECT_EQ(33, STAN_MINOR);
+  EXPECT_EQ(34, STAN_MINOR);
   EXPECT_EQ(0, STAN_PATCH);
 }
 
 TEST(Stan, version) {
   EXPECT_EQ("2", stan::MAJOR_VERSION);
-  EXPECT_EQ("33", stan::MINOR_VERSION);
+  EXPECT_EQ("34", stan::MINOR_VERSION);
   EXPECT_EQ("0", stan::PATCH_VERSION);
 }