diff --git a/.github/bors.toml b/.github/bors.toml
index 63d883fd..9af0108f 100644
--- a/.github/bors.toml
+++ b/.github/bors.toml
@@ -3,7 +3,7 @@ delete_merged_branches = true
 required_approvals = 1
 status = [
   "ci-linux (stable)",
-  "ci-linux (1.38.0)",
+  "ci-linux (1.59.0)",
   "rustfmt",
   "clippy",
 ]
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e792872a..7006c5eb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,7 +17,7 @@ jobs:
 
         include:
           # Test MSRV
-          - rust: 1.38.0
+          - rust: 1.59.0
             features: ""
 
           # Test nightly but don't fail
diff --git a/Cargo.toml b/Cargo.toml
index a79bc3c1..dc067989 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,6 +27,10 @@ version = "1"
 features = [ "derive" ]
 optional = true
 
+[dependencies.serde_json]
+version = "1"
+optional = true
+
 [features]
 cm7 = []
 cm7-r0p1 = ["cm7"]
diff --git a/README.md b/README.md
index 6bd8aedd..a0457651 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@ This project is developed and maintained by the [Cortex-M team][team].
 
 ## Minimum Supported Rust Version (MSRV)
 
-This crate is guaranteed to compile on stable Rust 1.38 and up. It might compile with older versions but that may change in any new patch release.
+This crate is guaranteed to compile on stable Rust 1.59 and up. It might compile with older versions but that may change in any new patch release.
 
 ## License
 
diff --git a/src/lib.rs b/src/lib.rs
index 044085ed..4ba0ad86 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -63,7 +63,7 @@
 //!
 //! # Minimum Supported Rust Version (MSRV)
 //!
-//! This crate is guaranteed to compile on stable Rust 1.38 and up. It *might*
+//! This crate is guaranteed to compile on stable Rust 1.59 and up. It *might*
 //! compile with older versions but that may change in any new patch release.
 
 #![deny(missing_docs)]
diff --git a/src/peripheral/scb.rs b/src/peripheral/scb.rs
index f998b17c..ecf98e5a 100644
--- a/src/peripheral/scb.rs
+++ b/src/peripheral/scb.rs
@@ -172,25 +172,8 @@ impl SCB {
     pub fn vect_active() -> VectActive {
         let icsr = unsafe { ptr::read(&(*SCB::PTR).icsr as *const _ as *const u32) };
 
-        match icsr as u8 {
-            0 => VectActive::ThreadMode,
-            2 => VectActive::Exception(Exception::NonMaskableInt),
-            3 => VectActive::Exception(Exception::HardFault),
-            #[cfg(not(armv6m))]
-            4 => VectActive::Exception(Exception::MemoryManagement),
-            #[cfg(not(armv6m))]
-            5 => VectActive::Exception(Exception::BusFault),
-            #[cfg(not(armv6m))]
-            6 => VectActive::Exception(Exception::UsageFault),
-            #[cfg(any(armv8m, native))]
-            7 => VectActive::Exception(Exception::SecureFault),
-            11 => VectActive::Exception(Exception::SVCall),
-            #[cfg(not(armv6m))]
-            12 => VectActive::Exception(Exception::DebugMonitor),
-            14 => VectActive::Exception(Exception::PendSV),
-            15 => VectActive::Exception(Exception::SysTick),
-            irqn => VectActive::Interrupt { irqn: irqn - 16 },
-        }
+        // NOTE(unsafe): Assume correctly selected target.
+        unsafe { VectActive::from(icsr as u8).unwrap_unchecked() }
     }
 }
 
@@ -300,7 +283,7 @@ impl VectActive {
             12 => VectActive::Exception(Exception::DebugMonitor),
             14 => VectActive::Exception(Exception::PendSV),
             15 => VectActive::Exception(Exception::SysTick),
-            irqn if irqn >= 16 => VectActive::Interrupt { irqn },
+            irqn if irqn >= 16 => VectActive::Interrupt { irqn: irqn - 16 },
             _ => return None,
         })
     }
diff --git a/xtask/tests/ci.rs b/xtask/tests/ci.rs
index ded7555c..b7bfc3dc 100644
--- a/xtask/tests/ci.rs
+++ b/xtask/tests/ci.rs
@@ -58,8 +58,6 @@ fn check_crates_build(is_nightly: bool, is_msrv: bool) {
             // Relies on all crates in this repo to use the same convention.
             let should_use_feature = |feat: &str| {
                 match feat {
-                    // critical-section doesn't build in 1.38 due to using `#[doc(include_str!(..))]`
-                    "critical-section-single-core" => !is_msrv,
                     // This is nightly-only, so don't use it on stable.
                     "inline-asm" => is_nightly,
                     // This only affects thumbv7em targets.
@@ -105,7 +103,7 @@ fn main() {
 
     let output = Command::new("rustc").arg("-V").output().unwrap();
     let is_nightly = str::from_utf8(&output.stdout).unwrap().contains("nightly");
-    let is_msrv = str::from_utf8(&output.stdout).unwrap().contains("1.38");
+    let is_msrv = str::from_utf8(&output.stdout).unwrap().contains("1.59");
 
     check_crates_build(is_nightly, is_msrv);