diff --git a/12_integrated_testing/Cargo.lock b/12_integrated_testing/Cargo.lock
index 9dac661b..00965470 100644
--- a/12_integrated_testing/Cargo.lock
+++ b/12_integrated_testing/Cargo.lock
@@ -24,9 +24,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.24"
+version = "1.0.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e0704ee1a7e00d7bb417d0770ea303c1bccbabf0ef1667dae92b5967f5f8a71"
+checksum = "a152013215dca273577e18d2bf00fa862b89b24169fb78c4c95aeb07992c9cec"
 dependencies = [
  "unicode-xid",
 ]
@@ -57,9 +57,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.62"
+version = "1.0.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "123a78a3596b24fee53a6464ce52d8ecbf62241e6294c7e7fe12086cd161f512"
+checksum = "3ce15dd3ed8aa2f8eeac4716d6ef5ab58b6b9256db41d7e1a0224c2788e8fd87"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/13_exceptions_part2_peripheral_IRQs/Cargo.lock b/13_exceptions_part2_peripheral_IRQs/Cargo.lock
index 922341af..ed950100 100644
--- a/13_exceptions_part2_peripheral_IRQs/Cargo.lock
+++ b/13_exceptions_part2_peripheral_IRQs/Cargo.lock
@@ -24,9 +24,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.24"
+version = "1.0.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e0704ee1a7e00d7bb417d0770ea303c1bccbabf0ef1667dae92b5967f5f8a71"
+checksum = "a152013215dca273577e18d2bf00fa862b89b24169fb78c4c95aeb07992c9cec"
 dependencies = [
  "unicode-xid",
 ]
@@ -57,9 +57,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.62"
+version = "1.0.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "123a78a3596b24fee53a6464ce52d8ecbf62241e6294c7e7fe12086cd161f512"
+checksum = "3ce15dd3ed8aa2f8eeac4716d6ef5ab58b6b9256db41d7e1a0224c2788e8fd87"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/14_virtual_mem_part2_mmio_remap/Cargo.lock b/14_virtual_mem_part2_mmio_remap/Cargo.lock
index e1591cd4..24a35e1d 100644
--- a/14_virtual_mem_part2_mmio_remap/Cargo.lock
+++ b/14_virtual_mem_part2_mmio_remap/Cargo.lock
@@ -24,9 +24,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.24"
+version = "1.0.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e0704ee1a7e00d7bb417d0770ea303c1bccbabf0ef1667dae92b5967f5f8a71"
+checksum = "a152013215dca273577e18d2bf00fa862b89b24169fb78c4c95aeb07992c9cec"
 dependencies = [
  "unicode-xid",
 ]
@@ -57,9 +57,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.62"
+version = "1.0.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "123a78a3596b24fee53a6464ce52d8ecbf62241e6294c7e7fe12086cd161f512"
+checksum = "3ce15dd3ed8aa2f8eeac4716d6ef5ab58b6b9256db41d7e1a0224c2788e8fd87"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/15_virtual_mem_part3_precomputed_tables/Cargo.lock b/15_virtual_mem_part3_precomputed_tables/Cargo.lock
index 62c78322..cc404144 100644
--- a/15_virtual_mem_part3_precomputed_tables/Cargo.lock
+++ b/15_virtual_mem_part3_precomputed_tables/Cargo.lock
@@ -24,9 +24,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.24"
+version = "1.0.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e0704ee1a7e00d7bb417d0770ea303c1bccbabf0ef1667dae92b5967f5f8a71"
+checksum = "a152013215dca273577e18d2bf00fa862b89b24169fb78c4c95aeb07992c9cec"
 dependencies = [
  "unicode-xid",
 ]
@@ -57,9 +57,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.62"
+version = "1.0.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "123a78a3596b24fee53a6464ce52d8ecbf62241e6294c7e7fe12086cd161f512"
+checksum = "3ce15dd3ed8aa2f8eeac4716d6ef5ab58b6b9256db41d7e1a0224c2788e8fd87"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/16_virtual_mem_part4_higher_half_kernel/Cargo.lock b/16_virtual_mem_part4_higher_half_kernel/Cargo.lock
index ba2e9eb5..5703573b 100644
--- a/16_virtual_mem_part4_higher_half_kernel/Cargo.lock
+++ b/16_virtual_mem_part4_higher_half_kernel/Cargo.lock
@@ -24,9 +24,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.24"
+version = "1.0.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e0704ee1a7e00d7bb417d0770ea303c1bccbabf0ef1667dae92b5967f5f8a71"
+checksum = "a152013215dca273577e18d2bf00fa862b89b24169fb78c4c95aeb07992c9cec"
 dependencies = [
  "unicode-xid",
 ]
@@ -57,9 +57,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.62"
+version = "1.0.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "123a78a3596b24fee53a6464ce52d8ecbf62241e6294c7e7fe12086cd161f512"
+checksum = "3ce15dd3ed8aa2f8eeac4716d6ef5ab58b6b9256db41d7e1a0224c2788e8fd87"
 dependencies = [
  "proc-macro2",
  "quote",