diff --git a/tb/axis_adapter/test_axis_adapter.py b/tb/axis_adapter/test_axis_adapter.py
index 486ac879c450db6cc4b9cf706fcebf9d70899ce4..addc7274575cf45a2a6e3f6c1052dacac03e367f 100644
--- a/tb/axis_adapter/test_axis_adapter.py
+++ b/tb/axis_adapter/test_axis_adapter.py
@@ -46,7 +46,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_arb_mux/test_axis_arb_mux.py b/tb/axis_arb_mux/test_axis_arb_mux.py
index dfe264b94ff432ced5bcfad6ba0f04ce10116cb1..ec23a41c7a80eb31c8a4181063409e8b596d7b18 100644
--- a/tb/axis_arb_mux/test_axis_arb_mux.py
+++ b/tb/axis_arb_mux/test_axis_arb_mux.py
@@ -49,7 +49,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = [AxiStreamSource(AxiStreamBus.from_prefix(dut, f"s{k:02d}_axis"), dut.clk, dut.rst) for k in range(ports)]
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_async_fifo/test_axis_async_fifo.py b/tb/axis_async_fifo/test_axis_async_fifo.py
index e064f98b43608ee9be038f984754aac14f7d7a63..223a7e36c062dec830ce95a1fab1b2745e9b5979 100644
--- a/tb/axis_async_fifo/test_axis_async_fifo.py
+++ b/tb/axis_async_fifo/test_axis_async_fifo.py
@@ -49,8 +49,8 @@ class TB(object):
         s_clk = int(os.getenv("S_CLK", "10"))
         m_clk = int(os.getenv("M_CLK", "11"))
 
-        cocotb.fork(Clock(dut.s_clk, s_clk, units="ns").start())
-        cocotb.fork(Clock(dut.m_clk, m_clk, units="ns").start())
+        cocotb.start_soon(Clock(dut.s_clk, s_clk, units="ns").start())
+        cocotb.start_soon(Clock(dut.m_clk, m_clk, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.s_clk, dut.s_rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.m_clk, dut.m_rst)
diff --git a/tb/axis_async_fifo_adapter/test_axis_async_fifo_adapter.py b/tb/axis_async_fifo_adapter/test_axis_async_fifo_adapter.py
index e97504f997c81e867c238ae5d132e33963e695a7..6ff2ac88debed9a7cee28ef5a76b59f7c48e5b36 100644
--- a/tb/axis_async_fifo_adapter/test_axis_async_fifo_adapter.py
+++ b/tb/axis_async_fifo_adapter/test_axis_async_fifo_adapter.py
@@ -46,8 +46,8 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.s_clk, 10, units="ns").start())
-        cocotb.fork(Clock(dut.m_clk, 11, units="ns").start())
+        cocotb.start_soon(Clock(dut.s_clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.m_clk, 11, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.s_clk, dut.s_rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.m_clk, dut.m_rst)
diff --git a/tb/axis_broadcast/test_axis_broadcast.py b/tb/axis_broadcast/test_axis_broadcast.py
index 7099e51fd3f56db38025a25db4b0faf2c9973eba..8bc7ac9a9fb5f2f550cc1c72f0fbe0286f54ce30 100644
--- a/tb/axis_broadcast/test_axis_broadcast.py
+++ b/tb/axis_broadcast/test_axis_broadcast.py
@@ -48,7 +48,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = [AxiStreamSink(AxiStreamBus.from_prefix(dut, f"m{k:02d}_axis"), dut.clk, dut.rst) for k in range(ports)]
diff --git a/tb/axis_cobs_decode/test_axis_cobs_decode.py b/tb/axis_cobs_decode/test_axis_cobs_decode.py
index 54fe33ef1aee76e5dd256bf3c66c2ccbb93483e9..cd8aead032b529815f0c200cbff619ea7b4e9ede 100644
--- a/tb/axis_cobs_decode/test_axis_cobs_decode.py
+++ b/tb/axis_cobs_decode/test_axis_cobs_decode.py
@@ -112,7 +112,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_cobs_encode/test_axis_cobs_encode.py b/tb/axis_cobs_encode/test_axis_cobs_encode.py
index ad9a7b6abfc22383ea006bcc8faf5bc489816f7b..8bc01dfc52a8ac518bbbc8632d00502b887cf76a 100644
--- a/tb/axis_cobs_encode/test_axis_cobs_encode.py
+++ b/tb/axis_cobs_encode/test_axis_cobs_encode.py
@@ -113,7 +113,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_demux/test_axis_demux.py b/tb/axis_demux/test_axis_demux.py
index 355eac8086b9372ea6a5fa6002d87dfe8999ce4c..832b02118e1c79f57be7531f8e19c8bf024480cf 100644
--- a/tb/axis_demux/test_axis_demux.py
+++ b/tb/axis_demux/test_axis_demux.py
@@ -48,7 +48,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = [AxiStreamSink(AxiStreamBus.from_prefix(dut, f"m{k:02d}_axis"), dut.clk, dut.rst) for k in range(ports)]
diff --git a/tb/axis_fifo/test_axis_fifo.py b/tb/axis_fifo/test_axis_fifo.py
index d4bcf3ee4cd4be72796895db15f1e8819e50d0e1..61b5351dea5b856c2fb2f598f8d0c9bfbc9e132a 100644
--- a/tb/axis_fifo/test_axis_fifo.py
+++ b/tb/axis_fifo/test_axis_fifo.py
@@ -46,7 +46,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_fifo_adapter/test_axis_fifo_adapter.py b/tb/axis_fifo_adapter/test_axis_fifo_adapter.py
index e5575b44e6e54ab4c29214703df7c55398226f97..6ff21ca98c249f44bdae8a702ed9e4e506d2aa68 100644
--- a/tb/axis_fifo_adapter/test_axis_fifo_adapter.py
+++ b/tb/axis_fifo_adapter/test_axis_fifo_adapter.py
@@ -46,7 +46,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_frame_length_adjust/test_axis_frame_length_adjust.py b/tb/axis_frame_length_adjust/test_axis_frame_length_adjust.py
index 43d7d2f597a38a0d0874960425335d76c789bf46..5817f5c0d2cfb86593dec104ba1ec8e3a8554339 100644
--- a/tb/axis_frame_length_adjust/test_axis_frame_length_adjust.py
+++ b/tb/axis_frame_length_adjust/test_axis_frame_length_adjust.py
@@ -51,7 +51,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_frame_length_adjust_fifo/test_axis_frame_length_adjust_fifo.py b/tb/axis_frame_length_adjust_fifo/test_axis_frame_length_adjust_fifo.py
index 5bc902db76dd37e882af80b55998f284f4848431..b3403cd00cd320f4664ec53fd91d73746bdb4484 100644
--- a/tb/axis_frame_length_adjust_fifo/test_axis_frame_length_adjust_fifo.py
+++ b/tb/axis_frame_length_adjust_fifo/test_axis_frame_length_adjust_fifo.py
@@ -51,7 +51,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_mux/test_axis_mux.py b/tb/axis_mux/test_axis_mux.py
index 1f04e10b46b3b0da3d40a728dd16cdbc1f16d258..217b03ce6d542494297326f6c29d1a4027c8ab92 100644
--- a/tb/axis_mux/test_axis_mux.py
+++ b/tb/axis_mux/test_axis_mux.py
@@ -48,7 +48,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = [AxiStreamSource(AxiStreamBus.from_prefix(dut, f"s{k:02d}_axis"), dut.clk, dut.rst) for k in range(ports)]
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_pipeline_fifo/test_axis_pipeline_fifo.py b/tb/axis_pipeline_fifo/test_axis_pipeline_fifo.py
index 4ed2fb8858ac009103471105a41bf8c9a4d0b43b..830b0337662301422055c3e3175f7514fe81b2d2 100644
--- a/tb/axis_pipeline_fifo/test_axis_pipeline_fifo.py
+++ b/tb/axis_pipeline_fifo/test_axis_pipeline_fifo.py
@@ -46,7 +46,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_pipeline_register/test_axis_pipeline_register.py b/tb/axis_pipeline_register/test_axis_pipeline_register.py
index cbb3c01ab9c4778bad7f7af4f743c18b92be6835..a971e8e19d527b7019b5b1af8d3315420f9db349 100644
--- a/tb/axis_pipeline_register/test_axis_pipeline_register.py
+++ b/tb/axis_pipeline_register/test_axis_pipeline_register.py
@@ -46,7 +46,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_ram_switch/test_axis_ram_switch.py b/tb/axis_ram_switch/test_axis_ram_switch.py
index e0071deb900699ea66cd6b6fcaa4cf10c78ab4d6..422fcd843e1f936bc94e9244bf6e6145a0292717 100644
--- a/tb/axis_ram_switch/test_axis_ram_switch.py
+++ b/tb/axis_ram_switch/test_axis_ram_switch.py
@@ -50,7 +50,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = [AxiStreamSource(AxiStreamBus.from_prefix(dut, f"s{k:02d}_axis"), dut.clk, dut.rst) for k in range(s_count)]
         self.sink = [AxiStreamSink(AxiStreamBus.from_prefix(dut, f"m{k:02d}_axis"), dut.clk, dut.rst) for k in range(m_count)]
diff --git a/tb/axis_rate_limit/test_axis_rate_limit.py b/tb/axis_rate_limit/test_axis_rate_limit.py
index 00dd0a3c780ab27c8c3f2cd910a9b7be059108cf..170419df2affda23fd4a45b0b6e08815ac04c8ae 100644
--- a/tb/axis_rate_limit/test_axis_rate_limit.py
+++ b/tb/axis_rate_limit/test_axis_rate_limit.py
@@ -45,7 +45,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_register/test_axis_register.py b/tb/axis_register/test_axis_register.py
index 87a5e0234917f4dc33af4f72e70f9c18893f8983..bd9e3e794cb3114a942d8de953a038452f961332 100644
--- a/tb/axis_register/test_axis_register.py
+++ b/tb/axis_register/test_axis_register.py
@@ -46,7 +46,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_srl_fifo/test_axis_srl_fifo.py b/tb/axis_srl_fifo/test_axis_srl_fifo.py
index 634ad73bf916ea1feda1c3103ab7e6504a6e3196..e18fd8a88cf762035d035ccb41a9bebbc42355aa 100644
--- a/tb/axis_srl_fifo/test_axis_srl_fifo.py
+++ b/tb/axis_srl_fifo/test_axis_srl_fifo.py
@@ -46,7 +46,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_srl_register/test_axis_srl_register.py b/tb/axis_srl_register/test_axis_srl_register.py
index d9128c8df5ee40e41e918232aa2991a209f875fd..4dd1c0c37fd4f2bbb7f300d5149c7d03d56531ef 100644
--- a/tb/axis_srl_register/test_axis_srl_register.py
+++ b/tb/axis_srl_register/test_axis_srl_register.py
@@ -46,7 +46,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = AxiStreamSource(AxiStreamBus.from_prefix(dut, "s_axis"), dut.clk, dut.rst)
         self.sink = AxiStreamSink(AxiStreamBus.from_prefix(dut, "m_axis"), dut.clk, dut.rst)
diff --git a/tb/axis_switch/test_axis_switch.py b/tb/axis_switch/test_axis_switch.py
index 6bc84d1a79dc469b6090e99f2be25a70fc220a7f..9e250e3334ab54fb7809b11b001c944b42909f7a 100644
--- a/tb/axis_switch/test_axis_switch.py
+++ b/tb/axis_switch/test_axis_switch.py
@@ -50,7 +50,7 @@ class TB(object):
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.fork(Clock(dut.clk, 10, units="ns").start())
+        cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
 
         self.source = [AxiStreamSource(AxiStreamBus.from_prefix(dut, f"s{k:02d}_axis"), dut.clk, dut.rst) for k in range(s_count)]
         self.sink = [AxiStreamSink(AxiStreamBus.from_prefix(dut, f"m{k:02d}_axis"), dut.clk, dut.rst) for k in range(m_count)]