diff --git a/.github/workflows/build_cmake.yml b/.github/workflows/build_cmake.yml
index 6a179bc7..6b98c694 100644
--- a/.github/workflows/build_cmake.yml
+++ b/.github/workflows/build_cmake.yml
@@ -71,6 +71,29 @@ jobs:
         sudo apt update
         sudo apt install -y libx11-dev libgl1-mesa-dev libsdl2-dev
 
+    - name: "Install timing system dependencies: etherbone"
+      shell: bash
+      run: |
+        git clone --branch v2.1.3 --depth=1 https://ohwr.org/project/etherbone-core.git
+        cd etherbone-core/api
+        touch ChangeLog # add an empty changelog file which is required by autotools
+        sed -e "s%AC_MSG_ERROR%AC_MSG_NOTICE%g" -i configure.ac
+        autoreconf -i
+        ./configure
+        make -j
+        sudo make install
+
+    - name: "Install timing system dependencies: saftlib"
+      shell: bash
+      run: |
+        sudo apt-get -y install libsigc++-2.0-dev libxslt1-dev libboost-all-dev
+        git clone --branch v3.0.3 --depth=1 https://github.com/GSI-CS-CO/saftlib.git
+        cd saftlib
+        ./autogen.sh
+        ./configure
+        make
+        sudo make install
+
     # Temporary dependency, until we rely on the plugin system to load gr-digitizers blocks at runtime
     - name: Install picoscope libraries
       run: |
diff --git a/cmake/Dependencies.cmake b/cmake/Dependencies.cmake
index c111685d..01e653ed 100644
--- a/cmake/Dependencies.cmake
+++ b/cmake/Dependencies.cmake
@@ -9,7 +9,7 @@ FetchContent_Declare(
 FetchContent_Declare(
         graph-prototype
         GIT_REPOSITORY https://github.com/fair-acc/graph-prototype.git
-        GIT_TAG 953501708db91ecda21805b6e2dd8af1da50399c
+        GIT_TAG 7d22e962c7f67fee95fd98c38bdb32ccde78d616
 )
 
 FetchContent_Declare(
diff --git a/src/service/cmake/Dependencies.cmake b/src/service/cmake/Dependencies.cmake
index 3f4ca142..3c9d8bb4 100644
--- a/src/service/cmake/Dependencies.cmake
+++ b/src/service/cmake/Dependencies.cmake
@@ -5,7 +5,7 @@ include(FetchContent)
 FetchContent_Declare(
         gr-digitizers
         GIT_REPOSITORY https://github.com/fair-acc/gr-digitizers.git
-        GIT_TAG fe402e92b7e4cfc8ffc745f2349ab26b941fc8b9 # latest dev-prototype as of 2023-11-09
+        GIT_TAG 68b8bfc2880a4eac9ce978458be63729d9d88c01 # latest dev-prototype as of 2014-01-18
 )
 
 FetchContent_MakeAvailable(gr-digitizers)
diff --git a/src/service/gnuradio/test/CountSource.hpp b/src/service/gnuradio/test/CountSource.hpp
index b8da9694..b969806e 100644
--- a/src/service/gnuradio/test/CountSource.hpp
+++ b/src/service/gnuradio/test/CountSource.hpp
@@ -78,9 +78,8 @@ struct CountSource : public gr::Block<CountSource<T>> {
             }
         }
         if (!_pending_tags.empty() && _pending_tags[0].index == static_cast<gr::Tag::signed_index_type>(_produced)) {
-            this->output_tags()[0] = { 0, _pending_tags[0].map };
+            this->publishTag(_pending_tags[0].map, 0);
             _pending_tags.pop_front();
-            this->forwardTags();
         }
 
         const auto subspan = std::span(output.begin(), output.end()).first(n);
diff --git a/src/service/main.cpp b/src/service/main.cpp
index 6c0a8360..28617ddf 100644
--- a/src/service/main.cpp
+++ b/src/service/main.cpp
@@ -53,9 +53,7 @@ struct TestSource : public gr::Block<TestSource<T>> {
         }
 
         if (_produced == 0 && n > 0) {
-            auto &tag = this->output_tags()[0];
-            tag       = { 0, { { std::string(gr::tag::SIGNAL_MIN.key()), -0.3f }, { std::string(gr::tag::SIGNAL_MAX.key()), 0.3f } } };
-            this->forwardTags();
+            this->publishTag({ { std::string(gr::tag::SIGNAL_MIN.key()), -0.3f }, { std::string(gr::tag::SIGNAL_MAX.key()), 0.3f } }, 0);
         }
 
         const auto edgeLength = static_cast<std::size_t>(sample_rate / 200.f);
diff --git a/src/ui/cmake/Dependencies.cmake b/src/ui/cmake/Dependencies.cmake
index a08646da..392cfa36 100644
--- a/src/ui/cmake/Dependencies.cmake
+++ b/src/ui/cmake/Dependencies.cmake
@@ -49,7 +49,7 @@ FetchContent_Declare(
 FetchContent_Declare(
         graph-prototype
         GIT_REPOSITORY https://github.com/fair-acc/graph-prototype.git
-        GIT_TAG 953501708db91ecda21805b6e2dd8af1da50399c
+        GIT_TAG 7d22e962c7f67fee95fd98c38bdb32ccde78d616
 )
 
 FetchContent_MakeAvailable(imgui implot imgui-node-editor yaml-cpp stb opencmw-cpp plf_colony graph-prototype)
diff --git a/src/ui/flowgraph/datasource.cpp b/src/ui/flowgraph/datasource.cpp
index 2d3e495b..7d7d1e0b 100644
--- a/src/ui/flowgraph/datasource.cpp
+++ b/src/ui/flowgraph/datasource.cpp
@@ -40,17 +40,13 @@ struct SineSource : public gr::Block<SineSource<T>> {
         thread.join();
     }
 
-    std::make_signed_t<std::size_t>
-    available_samples(const SineSource & /*d*/) noexcept {
-        std::lock_guard lock(mutex);
-        const auto      ret = std::make_signed_t<std::size_t>(samples.size());
-        return ret > 0 ? ret : -1;
-    }
-
     T processOne() {
         std::lock_guard guard(mutex);
-
-        T               v = samples.front();
+        assert(!samples.empty());
+        if (samples.size() == 1) {
+            this->requestStop();
+        }
+        T v = samples.front();
         samples.pop_front();
         return v;
     }