diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8888f98..3582f2b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.8 FATAL_ERROR)
 
-project(timers VERSION 1.3.3 LANGUAGES CXX)
+project(timers VERSION 1.3.4 LANGUAGES CXX)
 
 add_library(${PROJECT_NAME} INTERFACE)
 
diff --git a/README.md b/README.md
index afda901..4a84390 100644
--- a/README.md
+++ b/README.md
@@ -1,22 +1,22 @@
-![Version](https://img.shields.io/badge/version-1.3.3-green.svg)
+![Version](https://img.shields.io/badge/version-1.3.4-green.svg)
 [![License](https://img.shields.io/badge/license-MIT_License-green.svg?style=flat)](LICENSE)
 [![Build Status](https://travis-ci.org/karel-burda/timers.svg?branch=master)](https://travis-ci.org/karel-burda/timers)
 [![Codecov Status](https://codecov.io/gh/karel-burda/timers/branch/master/graph/badge.svg)](https://codecov.io/gh/karel-burda/timers/branch/master)
 
-# Important
+## Important
 This project contains git sub-modules that are needed for building example and tests.
 
 If you just want to use the implementation, you can clone without sub-modules. In case you want to build the example or tests, be sure to clone the repository
 with `--recurse-submodules` or `--recursive` on older versions of git. Alternatively, you can clone without sub-modules and initialize these later.
 
-# Introduction
+## Introduction
 `timers` features a thread-safe and header-only library that's implementing timer-related functionality and provides following features:
-* General blocking timer: `blocking`
-* Single-shot timer that does given action after time period expires: `single_shot`
-* Its asynchronous version: `single_shot_async`
-* Timer that does some action periodically: `periodic`
-* Its asynchronous version: `periodic_async`
-* Scoped "RAII" timer that stops underlying timer automatically upon destruction: `scoped`
+  * General blocking timer: `blocking`
+  * Single-shot timer that does given action after time period expires: `single_shot`
+  * Its asynchronous version: `single_shot_async`
+  * Timer that does some action periodically: `periodic`
+  * Its asynchronous version: `periodic_async`
+  * Scoped "RAII" timer that stops underlying timer automatically upon destruction: `scoped`
 
 Implemented using C++11 with the use of `std::conditional_variable`, `std::promise` and `std::async`.
 
@@ -24,27 +24,27 @@ Client defines timer's action that should be of type `timers::callback`, thus `s
 Time intervals are being defined as `timers::interval` = `std::chrono::duration<double>`.
 
 Implementation might throw these exceptions upon the `start(...)`:
-* `callback_not_callable`
-* `time_period_is_zero`
-* `time_period_is_negative`
+  * `callback_not_callable`
+  * `time_period_is_zero`
+  * `time_period_is_negative`
 
 See [exceptions.hpp](include/timers/exceptions.hpp) for more info.
 
 Policies specifies how timer class will behave when exception is thrown from the user's callback:
-* `stop` -- causes the timer to call `stop()` on itself and re-throws catched exception
-* `ignore` -- causes the timer to ignore catched exception and keep on working
+  * `stop` -- causes the timer to call `stop()` on itself and re-throws catched exception
+  * `ignore` -- causes the timer to ignore catched exception and keep on working
 
 See [policies.hpp](include/timers/policies.hpp).
 
-# Usage
+## Usage
 Implementation resides in the `burda::timers` namespace, so it might be useful to do `namespace timers = burda::timers;` in your project.
 
-## 1. CMake Way
+### 1. CMake Way
 Recommended option.
 
 There are essentially these ways of how to use this package depending on your preferences our build architecture:
 
-### A) Generate directly
+#### A) Generate directly
 
 Call `add_subdirectory(...)` directly in your CMakeLists.txt:
 
@@ -64,7 +64,7 @@ target_link_libraries(my-project timers)
 # or with private visibility: target_link_libraries(my-project PRIVATE timers)
 ```
 
-### B) Generate separately
+#### B) Generate separately
 
 Generation phase on the timers is run separately, that means that you run:
 ```cmake
@@ -90,14 +90,14 @@ target_link_libraries(my-project burda::timers)
 # or with public visibility: target_link_libraries(my-project PUBLIC burda::timers)
 ```
 
-## 2. Manual Way
+### 2. Manual Way
 Not recommended.
 
 Make sure that the `include` directory is in the search paths.
 
 You also have to set C++ 11 standard and potentially other settings as well (e.g. linking `pthread` on POSIXes, etc.).
 
-# Example
+## Examples
 For full use cases, see [main.cpp](example/src/main.cpp) or implementation of unit tests at [tests/unit](tests/unit).
 
 ### Blocking
@@ -203,7 +203,7 @@ foo.work();
 
 For full use cases, see [main.cpp](example/src/main.cpp) or implementation of unit tests at [tests/unit](tests/unit).
 
-# Unit Tests
+## Unit Tests
 Tests require sub-modules [cmake-helpers](https://github.com/karel-burda/cmake-helpers), [cpp-utils](https://github.com/karel-burda/cpp-utils) and [test-utils](https://github.com/karel-burda/test-utils).
 
 For building tests, run CMake in the source directory [tests/unit](tests/unit):
@@ -228,7 +228,7 @@ This is the example of running tests in the debug mode.
 
 For more info, see [.travis.yml](.travis.yml).
 
-# Continuous Integration
+## Continuous Integration
 Continuous Integration is now being run Linux, OS X and Windows on Travis: https://travis-ci.org/karel-burda/timers.
 
 Compilers are set-up to treat warnings as errors and with pedantic warning level.
@@ -237,8 +237,8 @@ Targets are built in one stage with debug symbols with code coverage measure and
 Valgrind is being run on the example as well.
 
 The project is using these jobs:
-* `timers, example, tests -- linux, debug, cppcheck, valgrind, coverage, g++, 64-bit`
-* `timers, example, tests -- osx, release with debug info, clang++, 64-bit`
-* `timers, example, tests -- windows, release, msvc, 32-bit`
+  * `timers, example, tests -- linux, debug, cppcheck, valgrind, coverage, g++, 64-bit`
+  * `timers, example, tests -- osx, release with debug info, clang++, 64-bit`
+  * `timers, example, tests -- windows, release, msvc, 32-bit`
 
 Project uses [codecov.io](https://codecov.io/gh/karel-burda/timers) for code coverage summary.
diff --git a/submodules/cmake-helpers b/submodules/cmake-helpers
index c5a7b95..3a3c672 160000
--- a/submodules/cmake-helpers
+++ b/submodules/cmake-helpers
@@ -1 +1 @@
-Subproject commit c5a7b953cb33755c9e06534acd15ea476d589adb
+Subproject commit 3a3c672f038690ce9d22855c63b99a570ae2412a
diff --git a/submodules/cpp-utils b/submodules/cpp-utils
index 1c476f2..89739e2 160000
--- a/submodules/cpp-utils
+++ b/submodules/cpp-utils
@@ -1 +1 @@
-Subproject commit 1c476f231d2d3e3d24618a7e65007974917c118c
+Subproject commit 89739e2add774d7072faeb75851fb4ff46b6f500
diff --git a/submodules/test-utils b/submodules/test-utils
index e4ebea6..6e8fc19 160000
--- a/submodules/test-utils
+++ b/submodules/test-utils
@@ -1 +1 @@
-Subproject commit e4ebea6eb328b94b9a26b23a610dc9c7da7afa2d
+Subproject commit 6e8fc198f5920be675ae01a5ff0f9f7c98166a24