diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index fb396ced..6bce4eba 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -24,7 +24,7 @@ set(rscore_srcs
         mm/buddy/checkpoint.c
         mm/model_allocator.c
         mm/msg_allocator.c
-        parallel/parallel.c
+        parallel/timewarp.c
         serial/serial.c)
 
 if(MPI_FOUND)
diff --git a/src/ROOT-Sim.h b/src/ROOT-Sim.h
index d4b76a30..8b861e55 100644
--- a/src/ROOT-Sim.h
+++ b/src/ROOT-Sim.h
@@ -170,6 +170,11 @@ enum log_level {
 	LOG_SILENT //!< Emit no messages during the simulation.
 };
 
+enum synchronization_algorithm {
+	SERIAL = 1, //!< The simulation runs on the serial runtime
+	TIME_WARP, //!< The simulation runs using the optimistic Time Warp algorithm
+};
+
 /// A set of configurable values used by other modules
 struct simulation_configuration {
 	/// The number of LPs to be used in the simulation
@@ -190,7 +195,12 @@ struct simulation_configuration {
 	unsigned ckpt_interval;
 	/// If set, worker threads are bound to physical cores
 	bool core_binding;
-	/// If set, the simulation will run on the serial runtime
+	/// Specify what synchronization algorithm we are using
+	enum synchronization_algorithm synchronization;
+	/**
+	 * @deprecated since 3.1.0
+	 * If set, the simulation will run on the serial runtime
+	 */
 	bool serial;
 	/// Function pointer to the dispatching function
 	ProcessEvent_t dispatcher;
diff --git a/src/gvt/termination.c b/src/gvt/termination.c
index 74d389cb..3ef725f6 100644
--- a/src/gvt/termination.c
+++ b/src/gvt/termination.c
@@ -86,7 +86,7 @@ void termination_on_gvt(const simtime_t current_gvt)
  */
 void RootsimStop(void)
 {
-	if(global_config.serial) {
+	if(global_config.synchronization == SERIAL) {
 		global_config.termination_time = -1.0;
 		return;
 	}
diff --git a/src/init.c b/src/init.c
index 38347780..71c4781e 100644
--- a/src/init.c
+++ b/src/init.c
@@ -17,7 +17,6 @@
 
 #include <ROOT-Sim.h>
 
-#include <inttypes.h>
 #include <string.h>
 
 /// A flag to check if the core library has been initialized correctly
@@ -54,14 +53,21 @@ static void print_config(void)
 	else
 		fprintf(stderr, "%lf\n", global_config.termination_time);
 
-	if(global_config.serial) {
-		fprintf(stderr, "Parallelism: sequential simulation\n");
-	} else {
+	switch (global_config.synchronization) {
+		case SERIAL:
+			fprintf(stderr, "Parallelism: sequential simulation\n");
+			break;
+		case TIME_WARP:
+			fprintf(stderr, "Parallelism: optimistic synchronization\n");
+			break;
+	}
+	if (global_config.synchronization != SERIAL) {
 		if(n_nodes > 1)
 			fprintf(stderr, "Parallelism: %d MPI processes\n", n_nodes);
 		else
 			fprintf(stderr, "Parallelism: %u threads\n", global_config.n_threads);
 	}
+
 	fprintf(stderr, "Thread-to-core binding: %s\n", global_config.core_binding ? "enabled" : "disabled");
 
 	fprintf(stderr, "GVT period: %u ms\n", global_config.gvt_period / 1000);
@@ -69,7 +75,7 @@ static void print_config(void)
 	if(global_config.ckpt_interval) {
 		fprintf(stderr, "Checkpoint interval: %u events\n", global_config.ckpt_interval);
 	} else {
-		if(!global_config.serial)
+		if(global_config.synchronization != SERIAL)
 			fprintf(stderr, "Checkpoint interval: auto\n");
 	}
 
@@ -108,9 +114,19 @@ int RootsimInit(const struct simulation_configuration *conf)
 		return -1;
 	}
 
+	if (global_config.serial) {
+		fprintf(stderr, "Using the deprecated `serial` configuration flag. Please swith to `.synchronization = SERIAL` instead\n");
+		global_config.synchronization = SERIAL;
+	}
+
+	if (unlikely(global_config.synchronization == 0)) {
+		fprintf(stderr, "No synchronization algorithm specified.\n");
+		return -1;
+	}
+
 	log_init(global_config.logfile);
 
-	if(global_config.serial)
+	if(global_config.synchronization == SERIAL)
 		global_config.n_threads = 1;
 	else if(global_config.n_threads == 0)
 		global_config.n_threads = thread_cores_count();
@@ -138,7 +154,7 @@ int RootsimRun(void)
 	if(!configuration_done)
 		return -1;
 
-	if(!global_config.serial)
+	if(global_config.synchronization == TIME_WARP)
 		mpi_global_init(NULL, NULL);
 
 	if(global_config.log_level < LOG_SILENT && !rid) {
@@ -146,7 +162,7 @@ int RootsimRun(void)
 		print_config();
 	}
 
-	if(global_config.serial) {
+	if(global_config.synchronization == SERIAL) {
 		ret = serial_simulation();
 	} else {
 		ret = parallel_simulation();
diff --git a/src/lp/process.c b/src/lp/process.c
index 965430a9..acc597a8 100644
--- a/src/lp/process.c
+++ b/src/lp/process.c
@@ -62,7 +62,7 @@ static _Thread_local struct lp_msg *current_msg;
 void ScheduleNewEvent(const lp_id_t receiver, const simtime_t timestamp, const unsigned event_type, const void *payload,
     unsigned payload_size)
 {
-	if(unlikely(global_config.serial)) {
+	if(unlikely(global_config.synchronization == SERIAL)) {
 		ScheduleNewEvent_serial(receiver, timestamp, event_type, payload, payload_size);
 		return;
 	}
diff --git a/src/parallel/parallel.c b/src/parallel/timewarp.c
similarity index 100%
rename from src/parallel/parallel.c
rename to src/parallel/timewarp.c
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 56ba32bf..9ac3ad43 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -41,7 +41,7 @@ test_program_link_libraries(sync rscore)
 # Integration tests
 test_program(correctness_serial integration/correctness/serial.c integration/correctness/application.c integration/correctness/functions.c integration/correctness/output_256.c)
 test_program_link_libraries(correctness_serial rscore)
-test_program(correctness_parallel integration/correctness/parallel.c integration/correctness/application.c integration/correctness/functions.c integration/correctness/output_256.c)
+test_program(correctness_parallel integration/correctness/timewarp.c integration/correctness/application.c integration/correctness/functions.c integration/correctness/output_256.c)
 test_program_link_libraries(correctness_parallel rscore)
 test_program(phold integration/phold.c)
 test_program_link_libraries(phold rscore)
diff --git a/test/core/load.c b/test/core/load.c
index 0e6319d6..a5611e08 100644
--- a/test/core/load.c
+++ b/test/core/load.c
@@ -27,10 +27,24 @@ static struct simulation_configuration conf = {
     .committed = NULL,
 };
 
+static const struct simulation_configuration no_synchronization = {
+	.lps = 1,
+	.dispatcher = DummyProcessEvent,
+	.committed = DummyCanEnd,
+};
+
 static const struct simulation_configuration valid_conf = {
-    .lps = 1,
-    .dispatcher = DummyProcessEvent,
-    .committed = DummyCanEnd,
+	.lps = 1,
+	.dispatcher = DummyProcessEvent,
+	.committed = DummyCanEnd,
+	.synchronization = TIME_WARP,
+};
+
+static const struct simulation_configuration deprecated_conf = {
+	.lps = 1,
+	.dispatcher = DummyProcessEvent,
+	.committed = DummyCanEnd,
+	.serial = true,
 };
 
 static int run_rootsim(_unused void *_)
@@ -62,6 +76,13 @@ int main(void)
 	test_xf("CanEnd not set", init_rootsim, &conf);
 	test_xf("Start simulation with no CanEnd", run_rootsim, NULL);
 
+	memcpy(&conf, &no_synchronization, sizeof(conf));
+	test_xf("No synchronization algorithm", init_rootsim, &conf);
+	test_xf("Start simulation with no synchronization algorithm", run_rootsim, NULL);
+
+	memcpy(&conf, &deprecated_conf, sizeof(conf));
+	test("Legacy serial flag", init_rootsim, &conf);
+
 	memcpy(&conf, &valid_conf, sizeof(conf));
 	test("Initialization", init_rootsim, &conf);
 	test("Dummy simulation", run_rootsim, NULL);
diff --git a/test/gvt/termination.c b/test/gvt/termination.c
index d1f5b300..cf1726c0 100644
--- a/test/gvt/termination.c
+++ b/test/gvt/termination.c
@@ -30,10 +30,10 @@ static bool DummyCanEnd(_unused lp_id_t lid, _unused const void *state)
 }
 
 static struct simulation_configuration serial_conf = {
-    .lps = 1, .dispatcher = DummyProcessEvent, .committed = DummyCanEnd, .serial = true};
+    .lps = 1, .dispatcher = DummyProcessEvent, .committed = DummyCanEnd, .synchronization = SERIAL};
 
 static struct simulation_configuration parallel_conf = {
-    .lps = 1, .dispatcher = DummyProcessEvent, .committed = DummyCanEnd, .serial = false};
+    .lps = 1, .dispatcher = DummyProcessEvent, .committed = DummyCanEnd, .synchronization = TIME_WARP};
 
 static int force_termination_test(void *conf)
 {
diff --git a/test/integration/correctness/serial.c b/test/integration/correctness/serial.c
index 9292d7e8..11a5563f 100644
--- a/test/integration/correctness/serial.c
+++ b/test/integration/correctness/serial.c
@@ -19,7 +19,7 @@ struct simulation_configuration conf = {
     .stats_file = NULL,
     .ckpt_interval = 0,
     .core_binding = false,
-    .serial = true,
+    .synchronization = SERIAL,
     .dispatcher = ProcessEvent,
     .committed = CanEnd,
 };
diff --git a/test/integration/correctness/parallel.c b/test/integration/correctness/timewarp.c
similarity index 95%
rename from test/integration/correctness/parallel.c
rename to test/integration/correctness/timewarp.c
index 1f0946ab..069cd314 100644
--- a/test/integration/correctness/parallel.c
+++ b/test/integration/correctness/timewarp.c
@@ -19,7 +19,7 @@ struct simulation_configuration conf = {
     .stats_file = NULL,
     .ckpt_interval = 0,
     .core_binding = false,
-    .serial = false,
+    .synchronization = TIME_WARP,
     .dispatcher = ProcessEvent,
     .committed = CanEnd,
 };
diff --git a/test/integration/phold.c b/test/integration/phold.c
index e97b6f82..99878970 100644
--- a/test/integration/phold.c
+++ b/test/integration/phold.c
@@ -106,7 +106,7 @@ struct simulation_configuration conf = {
     .stats_file = "phold",
     .ckpt_interval = 0,
     .core_binding = true,
-    .serial = false,
+    .synchronization = TIME_WARP,
     .dispatcher = ProcessEvent,
     .committed = CanEnd,
 };
diff --git a/test/log/rootsim_stats_test.py b/test/log/rootsim_stats_test.py
index 618fca46..79d3e6ee 100644
--- a/test/log/rootsim_stats_test.py
+++ b/test/log/rootsim_stats_test.py
@@ -99,6 +99,7 @@ def test_stats_file(base_name, expected):
             if float(match[i + 1]) == 0:
                 sys.exit(1)
         elif expected_field != match[i + 1]:
+            print(f"Error in {base_name} at field {i + 1}: expected '{expected_field}', got '{match[i + 1]}'")
             sys.exit(1)
 
 
diff --git a/test/log/stats.c b/test/log/stats.c
index 6eb8302f..7cd37b8c 100644
--- a/test/log/stats.c
+++ b/test/log/stats.c
@@ -39,7 +39,7 @@ static struct simulation_configuration conf = {
     .stats_file = NULL,
     .ckpt_interval = 0,
     .core_binding = true,
-    .serial = false,
+    .synchronization = TIME_WARP,
     .dispatcher = DummyProcessEvent,
     .committed = DummyCanEnd,
 };