diff --git a/Cargo.lock b/Cargo.lock
index 5cbb1d8f..4a1c745d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -80,7 +80,6 @@ version = "0.0.0"
 dependencies = [
  "serde",
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -200,7 +199,6 @@ dependencies = [
  "serde_json",
  "trybuild",
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -238,7 +236,6 @@ version = "0.0.0"
 dependencies = [
  "usdt",
  "usdt-tests-common",
- "version_check",
 ]
 
 [[package]]
@@ -278,7 +275,6 @@ name = "empty"
 version = "0.0.0"
 dependencies = [
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -292,7 +288,6 @@ name = "fake-cmd"
 version = "0.0.0"
 dependencies = [
  "fake-lib",
- "version_check",
 ]
 
 [[package]]
@@ -300,7 +295,6 @@ name = "fake-lib"
 version = "0.0.0"
 dependencies = [
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -529,7 +523,6 @@ version = "0.0.0"
 dependencies = [
  "serde",
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -645,7 +638,6 @@ version = "0.0.0"
 dependencies = [
  "serde",
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -653,7 +645,6 @@ name = "probe-test-build"
 version = "0.0.0"
 dependencies = [
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -661,7 +652,6 @@ name = "probe-test-macro"
 version = "0.0.0"
 dependencies = [
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -741,7 +731,6 @@ version = "0.0.0"
 dependencies = [
  "serde",
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -750,7 +739,6 @@ version = "0.0.0"
 dependencies = [
  "serde",
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -979,7 +967,6 @@ dependencies = [
  "tokio",
  "usdt",
  "usdt-tests-common",
- "version_check",
 ]
 
 [[package]]
@@ -988,7 +975,6 @@ version = "0.0.0"
 dependencies = [
  "subprocess",
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -1132,7 +1118,6 @@ name = "usdt"
 version = "0.5.0"
 dependencies = [
  "dof",
- "dtrace-parser",
  "goblin",
  "memmap2",
  "serde",
@@ -1169,7 +1154,6 @@ dependencies = [
  "syn",
  "thiserror",
  "thread-id",
- "version_check",
 ]
 
 [[package]]
@@ -1195,7 +1179,6 @@ dependencies = [
  "serde",
  "serde_json",
  "usdt",
- "version_check",
 ]
 
 [[package]]
@@ -1402,7 +1385,6 @@ name = "zero-arg-probe"
 version = "0.0.0"
 dependencies = [
  "usdt",
- "version_check",
 ]
 
 [[package]]
diff --git a/README.md b/README.md
index d438ae6d..7ebea767 100644
--- a/README.md
+++ b/README.md
@@ -225,58 +225,6 @@ comes with significant tradeoffs. As such the current recommendation is:
 function calling it), and document to their users that this function should be called to
 guarantee that probes are registered.
 
-## Notes
-
-The `usdt` crate requires [inline asm][inline-asm], a feature stabilized in Rust 1.59.
-Prior to that version, a nightly toolchain was required to import the feature.  For legacy
-convenience reasons, the crate contains also an empty, no-op implementation, which generates all the
-same probe macros, but with empty bodies (thus not requiring inline asm).  This may be selected by
-passing the `--no-default-features` flag when building the crate, or by using `default-features =
-false` in the [`[dependencies]` table][feature-deps] of one's `Cargo.toml`.
-
-Library developers may use `usdt` as an optional dependency, gated by a feature, for example
-named `usdt-probes` or similar. This feature would imply the `usdt/asm` feature, but the `usdt`
-crate could be used with the no-op implementation by default. For example, your `Cargo.toml`
-might contain
-
-```
-[dependencies]
-usdt = { version = "*", optional = true, default-features = false }
-
-# ... later
-
-[features]
-usdt-probes = ["usdt/asm"]
-```
-
-This allows users to opt into probes if they are using a suitably new toolchain, or and older
-nightly with the `asm` feature enabled on their project.
-
-### The Rust `asm` feature
-
-On toolchains prior to 1.59, inline asm was [not available][asm-issue] without the feature being
-enabled.  This applies to code _calling_ the probe macros, in addition to `usdt` where they are
-implemented.  Those generated probe macros must be in a module that is either built with a >=1.59
-toolchain or where the `feature(asm)` configuration is present.
-
-
-#### Toolchain versions and the `asm_sym` feature
-
-On macOS (where the linker is involved in USDT probe creation) on toolchains prior to 1.66, the
-`asm_sym` feature is required (in addition to `asm` in nightly toolchains prior to November 2021;
-see [this issue][asm-feature-flags]). For such a toolchain, this feature can be included just on
-macOS e.g., with `#![cfg_attr(target_os = "macos", feature(asm_sym))]`, or unconditionally on all
-platforms.
-
-The addition of the `asm_sym` feature presents an unfortunate problem. It is no longer possible to
-compile the `usdt` crate (or any crate defining probes) with a toolchain from before that feature
-was added _and_ after its addition. In the former case, we'd get errors about an unknown feature
-should we include the `asm_sym` feature, and we'd get errors about functionality behind a feature
-gate from later compilers should we omit the feature.
-
-Fortunately with the stabilization of `asm_sym` in 1.66, using this crate should become much
-simpler.
-
 ## References
 
 [1]: https://illumos.org/books/dtrace/chp-usdt.html#chp-usdt
@@ -285,7 +233,3 @@ simpler.
 [4]: https://docs.rs/serde_json/1.0.68/serde_json/fn.to_string.html
 [serde-json-error]: https://docs.serde.rs/serde_json/error/struct.Error.html
 [serde-runtime-fail]: https://github.com/serde-rs/serde/issues/1307
-[inline-asm]: https://github.com/rust-lang/rust/issues/72016
-[feature-deps]: https://doc.rust-lang.org/cargo/reference/features.html#dependency-features
-[asm-issue]: https://github.com/rust-lang/rust/issues/72016
-[asm-feature-flags]: https://github.com/rust-lang/rust/pull/90348
diff --git a/common-build.rs b/common-build.rs
deleted file mode 100644
index 15cb9897..00000000
--- a/common-build.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-// Copyright 2022 Oxide Computer Company
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-
-    if !version_check::is_min_version("1.59").unwrap_or(false) {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm");
-    }
-    #[cfg(target_os = "macos")]
-    if version_check::supports_feature("asm_sym").unwrap_or(false)
-        && !version_check::is_min_version("1.67").unwrap_or(false)
-    {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm_sym");
-    }
-}
diff --git a/dusty/Cargo.toml b/dusty/Cargo.toml
index faad6f90..c6984981 100644
--- a/dusty/Cargo.toml
+++ b/dusty/Cargo.toml
@@ -10,5 +10,5 @@ publish = false
 [dependencies]
 clap = { version = "4.5.11", features = ["derive"] }
 dof = { path = "../dof", features = ["des"] }
-usdt = { path = "../usdt", features = ["asm"] }
+usdt = { path = "../usdt" }
 usdt-impl = { path = "../usdt-impl", features = ["des"] }
diff --git a/probe-test-attr/Cargo.toml b/probe-test-attr/Cargo.toml
index 46bc1092..0163c1b8 100644
--- a/probe-test-attr/Cargo.toml
+++ b/probe-test-attr/Cargo.toml
@@ -7,10 +7,3 @@ publish = false
 [dependencies]
 usdt = { path = "../usdt", default-features = false }
 serde = "1"
-
-[build-dependencies]
-version_check = "0.9.5"
-
-[features]
-default = ["asm"]
-asm = ["usdt/asm"]
diff --git a/probe-test-attr/src/main.rs b/probe-test-attr/src/main.rs
index 72de7905..b409c97a 100644
--- a/probe-test-attr/src/main.rs
+++ b/probe-test-attr/src/main.rs
@@ -15,9 +15,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
-
 use serde::Serialize;
 
 /// By deriving the `serde::Serialize` trait, the `Arg` struct can be used as an argument to a
diff --git a/probe-test-build/Cargo.toml b/probe-test-build/Cargo.toml
index 0cde71bc..086ccf94 100644
--- a/probe-test-build/Cargo.toml
+++ b/probe-test-build/Cargo.toml
@@ -9,8 +9,3 @@ usdt = { path = "../usdt", default-features = false }
 
 [build-dependencies]
 usdt = { path = "../usdt" }
-version_check = "0.9.5"
-
-[features]
-default = ["asm"]
-asm = ["usdt/asm"]
diff --git a/probe-test-build/build.rs b/probe-test-build/build.rs
index da15a410..5f5e6209 100644
--- a/probe-test-build/build.rs
+++ b/probe-test-build/build.rs
@@ -17,16 +17,6 @@ use usdt::Builder;
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
-    if !version_check::is_min_version("1.59").unwrap_or(false) {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm");
-    }
-    #[cfg(target_os = "macos")]
-    if version_check::supports_feature("asm_sym").unwrap_or(false)
-        && !version_check::is_min_version("1.67").unwrap_or(false)
-    {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm_sym");
-    }
-
     println!("cargo:rerun-if-changed=test.d");
     Builder::new("test.d").build().unwrap();
 }
diff --git a/probe-test-build/src/main.rs b/probe-test-build/src/main.rs
index 874415d9..21a29859 100644
--- a/probe-test-build/src/main.rs
+++ b/probe-test-build/src/main.rs
@@ -14,9 +14,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
-
 use std::thread::sleep;
 use std::time::Duration;
 
diff --git a/probe-test-macro/Cargo.toml b/probe-test-macro/Cargo.toml
index 1668f51f..1414397b 100644
--- a/probe-test-macro/Cargo.toml
+++ b/probe-test-macro/Cargo.toml
@@ -6,10 +6,3 @@ publish = false
 
 [dependencies]
 usdt = { path = "../usdt", default-features = false }
-
-[build-dependencies]
-version_check = "0.9.5"
-
-[features]
-default = ["asm"]
-asm = ["usdt/asm"]
diff --git a/probe-test-macro/src/main.rs b/probe-test-macro/src/main.rs
index 576b2511..4400e231 100644
--- a/probe-test-macro/src/main.rs
+++ b/probe-test-macro/src/main.rs
@@ -14,9 +14,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
-
 use std::thread::sleep;
 use std::time::Duration;
 
diff --git a/tests/argument-types/Cargo.toml b/tests/argument-types/Cargo.toml
index 58196148..c0a54244 100644
--- a/tests/argument-types/Cargo.toml
+++ b/tests/argument-types/Cargo.toml
@@ -7,6 +7,3 @@ publish = false
 [dependencies]
 usdt = { path = "../../usdt" }
 serde = "1"
-
-[build-dependencies]
-version_check = "0.9.5"
diff --git a/tests/argument-types/src/main.rs b/tests/argument-types/src/main.rs
index cd3fc5d8..ea6c31d6 100644
--- a/tests/argument-types/src/main.rs
+++ b/tests/argument-types/src/main.rs
@@ -15,8 +15,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
 use serde::Serialize;
 
 /// Most struct or tuple types implementing serde::Serialize may be used in probes.
diff --git a/tests/compile-errors/Cargo.toml b/tests/compile-errors/Cargo.toml
index d5a0ef6c..ffd47acb 100644
--- a/tests/compile-errors/Cargo.toml
+++ b/tests/compile-errors/Cargo.toml
@@ -11,6 +11,3 @@ serde_json = "*"
 
 [dev-dependencies]
 trybuild = "1.0.98"
-
-[build-dependencies]
-version_check = "0.9.5"
diff --git a/tests/does-it-work/Cargo.toml b/tests/does-it-work/Cargo.toml
index 55a76e15..cdb0d7e9 100644
--- a/tests/does-it-work/Cargo.toml
+++ b/tests/does-it-work/Cargo.toml
@@ -10,4 +10,3 @@ usdt-tests-common = { path = "../../usdt-tests-common" }
 
 [build-dependencies]
 usdt = { path = "../../usdt" }
-version_check = "0.9.5"
diff --git a/tests/does-it-work/build.rs b/tests/does-it-work/build.rs
index da15a410..5f5e6209 100644
--- a/tests/does-it-work/build.rs
+++ b/tests/does-it-work/build.rs
@@ -17,16 +17,6 @@ use usdt::Builder;
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
-    if !version_check::is_min_version("1.59").unwrap_or(false) {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm");
-    }
-    #[cfg(target_os = "macos")]
-    if version_check::supports_feature("asm_sym").unwrap_or(false)
-        && !version_check::is_min_version("1.67").unwrap_or(false)
-    {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm_sym");
-    }
-
     println!("cargo:rerun-if-changed=test.d");
     Builder::new("test.d").build().unwrap();
 }
diff --git a/tests/does-it-work/src/main.rs b/tests/does-it-work/src/main.rs
index 0098dfca..a61ae54e 100644
--- a/tests/does-it-work/src/main.rs
+++ b/tests/does-it-work/src/main.rs
@@ -16,8 +16,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
 #![allow(non_snake_case)]
 
 use usdt::register_probes;
diff --git a/tests/empty/Cargo.toml b/tests/empty/Cargo.toml
index 1d406ba2..bd59d742 100644
--- a/tests/empty/Cargo.toml
+++ b/tests/empty/Cargo.toml
@@ -11,10 +11,3 @@ default-features = false
 [build-dependencies.usdt]
 path = "../../usdt"
 default-features = false
-
-[build-dependencies]
-version_check = "0.9.5"
-
-[features]
-default = ["asm"]
-asm = ["usdt/asm"]
diff --git a/tests/empty/build.rs b/tests/empty/build.rs
index 82d5a027..e8ec29f6 100644
--- a/tests/empty/build.rs
+++ b/tests/empty/build.rs
@@ -17,16 +17,6 @@ use usdt::Builder;
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
-    if !version_check::is_min_version("1.59").unwrap_or(false) {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm");
-    }
-    #[cfg(target_os = "macos")]
-    if version_check::supports_feature("asm_sym").unwrap_or(false)
-        && !version_check::is_min_version("1.67").unwrap_or(false)
-    {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm_sym");
-    }
-
     println!("cargo:rerun-if-changed=provider.d");
     Builder::new("provider.d")
         .build()
diff --git a/tests/empty/src/main.rs b/tests/empty/src/main.rs
index 38399d9a..fc8d6134 100644
--- a/tests/empty/src/main.rs
+++ b/tests/empty/src/main.rs
@@ -12,8 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
 #![deny(warnings)]
 
 use usdt::register_probes;
diff --git a/tests/fake-cmd/Cargo.toml b/tests/fake-cmd/Cargo.toml
index 7a960baa..0efecaca 100644
--- a/tests/fake-cmd/Cargo.toml
+++ b/tests/fake-cmd/Cargo.toml
@@ -6,6 +6,3 @@ publish = false
 
 [dependencies]
 fake-lib = { path = "../fake-lib" }
-
-[build-dependencies]
-version_check = "0.9.5"
diff --git a/tests/fake-cmd/src/main.rs b/tests/fake-cmd/src/main.rs
index dfc4a453..25249f8a 100644
--- a/tests/fake-cmd/src/main.rs
+++ b/tests/fake-cmd/src/main.rs
@@ -12,8 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
 #![deny(warnings)]
 
 fn main() {
diff --git a/tests/fake-lib/Cargo.toml b/tests/fake-lib/Cargo.toml
index 3dda08b3..0faf7136 100644
--- a/tests/fake-lib/Cargo.toml
+++ b/tests/fake-lib/Cargo.toml
@@ -5,8 +5,7 @@ edition = "2021"
 publish = false
 
 [dependencies]
-usdt = { path = "../../usdt", features = ["asm"] }
+usdt = { path = "../../usdt" }
 
 [build-dependencies]
-usdt = { path = "../../usdt", features = ["asm"] }
-version_check = "0.9.5"
+usdt = { path = "../../usdt" }
diff --git a/tests/fake-lib/build.rs b/tests/fake-lib/build.rs
index da15a410..5f5e6209 100644
--- a/tests/fake-lib/build.rs
+++ b/tests/fake-lib/build.rs
@@ -17,16 +17,6 @@ use usdt::Builder;
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
-    if !version_check::is_min_version("1.59").unwrap_or(false) {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm");
-    }
-    #[cfg(target_os = "macos")]
-    if version_check::supports_feature("asm_sym").unwrap_or(false)
-        && !version_check::is_min_version("1.67").unwrap_or(false)
-    {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm_sym");
-    }
-
     println!("cargo:rerun-if-changed=test.d");
     Builder::new("test.d").build().unwrap();
 }
diff --git a/tests/fake-lib/src/lib.rs b/tests/fake-lib/src/lib.rs
index 697a29c0..5f859e79 100644
--- a/tests/fake-lib/src/lib.rs
+++ b/tests/fake-lib/src/lib.rs
@@ -12,8 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
 #![deny(warnings)]
 
 pub use usdt::register_probes;
diff --git a/tests/modules/Cargo.toml b/tests/modules/Cargo.toml
index 09b8cf13..74c16222 100644
--- a/tests/modules/Cargo.toml
+++ b/tests/modules/Cargo.toml
@@ -7,6 +7,3 @@ publish = false
 [dependencies]
 usdt = { path = "../../usdt" }
 serde = "1"
-
-[build-dependencies]
-version_check = "0.9.5"
diff --git a/tests/modules/src/main.rs b/tests/modules/src/main.rs
index 3c1abe10..ae9d8add 100644
--- a/tests/modules/src/main.rs
+++ b/tests/modules/src/main.rs
@@ -12,9 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
-
 mod inner;
 
 fn main() {
diff --git a/tests/rename-builder/Cargo.toml b/tests/rename-builder/Cargo.toml
index 555e3e42..04ddcf9b 100644
--- a/tests/rename-builder/Cargo.toml
+++ b/tests/rename-builder/Cargo.toml
@@ -10,4 +10,3 @@ serde = "1"
 
 [build-dependencies]
 usdt = { path = "../../usdt" }
-version_check = "0.9.5"
diff --git a/tests/rename-builder/build.rs b/tests/rename-builder/build.rs
index f048054c..727ab734 100644
--- a/tests/rename-builder/build.rs
+++ b/tests/rename-builder/build.rs
@@ -17,16 +17,6 @@ use usdt::Builder;
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
-    if !version_check::is_min_version("1.59").unwrap_or(false) {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm");
-    }
-    #[cfg(target_os = "macos")]
-    if version_check::supports_feature("asm_sym").unwrap_or(false)
-        && !version_check::is_min_version("1.67").unwrap_or(false)
-    {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm_sym");
-    }
-
     println!("cargo:rerun-if-changed=test.d");
     Builder::new("test.d").module("still_test").build().unwrap();
 }
diff --git a/tests/rename-builder/src/main.rs b/tests/rename-builder/src/main.rs
index eb3f96f8..18128205 100644
--- a/tests/rename-builder/src/main.rs
+++ b/tests/rename-builder/src/main.rs
@@ -15,8 +15,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
 include!(concat!(env!("OUT_DIR"), "/test.rs"));
 
 fn main() {
diff --git a/tests/rename/Cargo.toml b/tests/rename/Cargo.toml
index a259776e..db8c30db 100644
--- a/tests/rename/Cargo.toml
+++ b/tests/rename/Cargo.toml
@@ -7,6 +7,3 @@ publish = false
 [dependencies]
 usdt = { path = "../../usdt" }
 serde = "1"
-
-[build-dependencies]
-version_check = "0.9.5"
diff --git a/tests/rename/src/main.rs b/tests/rename/src/main.rs
index 854a7623..c08e886a 100644
--- a/tests/rename/src/main.rs
+++ b/tests/rename/src/main.rs
@@ -14,9 +14,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
-
 #[usdt::provider(provider = "something", probe_format = "probe_{probe}")]
 mod probes {
     fn something() {}
diff --git a/tests/test-json/Cargo.toml b/tests/test-json/Cargo.toml
index d483f6a8..185b134e 100644
--- a/tests/test-json/Cargo.toml
+++ b/tests/test-json/Cargo.toml
@@ -10,8 +10,5 @@ usdt-tests-common = { path = "../../usdt-tests-common" }
 serde = "*"
 serde_json = "*"
 
-[build-dependencies]
-version_check = "0.9.5"
-
 [dev-dependencies]
 tokio = { version = "1.39.2", features = [ "full" ] }
diff --git a/tests/test-json/src/main.rs b/tests/test-json/src/main.rs
index e36283fe..a4bde438 100644
--- a/tests/test-json/src/main.rs
+++ b/tests/test-json/src/main.rs
@@ -14,9 +14,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
-
 use serde::{Serialize, Serializer};
 
 // Expected error message from serialization failure
diff --git a/tests/test-unique-id/Cargo.toml b/tests/test-unique-id/Cargo.toml
index 7a8eae29..20d783b1 100644
--- a/tests/test-unique-id/Cargo.toml
+++ b/tests/test-unique-id/Cargo.toml
@@ -9,6 +9,3 @@ usdt = { path = "../../usdt" }
 
 [dev-dependencies]
 subprocess = "0.2"
-
-[build-dependencies]
-version_check = "0.9.5"
diff --git a/tests/test-unique-id/src/main.rs b/tests/test-unique-id/src/main.rs
index c03cf109..da70b888 100644
--- a/tests/test-unique-id/src/main.rs
+++ b/tests/test-unique-id/src/main.rs
@@ -14,9 +14,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
-
 #[usdt::provider]
 mod with_ids {
     use usdt::UniqueId;
diff --git a/tests/usize/Cargo.toml b/tests/usize/Cargo.toml
index f1986a48..17fa9db8 100644
--- a/tests/usize/Cargo.toml
+++ b/tests/usize/Cargo.toml
@@ -5,10 +5,9 @@ edition = "2021"
 publish = false
 
 [dependencies]
-usdt = { path = "../../usdt", features = ["asm"] }
+usdt = { path = "../../usdt" }
 serde = "*"
 serde_json = "*"
 
 [build-dependencies]
-usdt = { path = "../../usdt", features = ["asm"] }
-version_check = "0.9.5"
+usdt = { path = "../../usdt" }
diff --git a/tests/usize/src/main.rs b/tests/usize/src/main.rs
index e9bfca02..b8dc7ca5 100644
--- a/tests/usize/src/main.rs
+++ b/tests/usize/src/main.rs
@@ -14,9 +14,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
-
 #[usdt::provider]
 mod usize__test {
     fn emit_usize(_: usize) {}
diff --git a/tests/zero-arg-probe/Cargo.toml b/tests/zero-arg-probe/Cargo.toml
index 04b634e4..9a614ce3 100644
--- a/tests/zero-arg-probe/Cargo.toml
+++ b/tests/zero-arg-probe/Cargo.toml
@@ -9,4 +9,3 @@ usdt = { path = "../../usdt" }
 
 [build-dependencies]
 usdt = { path = "../../usdt" }
-version_check = "0.9.5"
diff --git a/tests/zero-arg-probe/build.rs b/tests/zero-arg-probe/build.rs
index da15a410..5f5e6209 100644
--- a/tests/zero-arg-probe/build.rs
+++ b/tests/zero-arg-probe/build.rs
@@ -17,16 +17,6 @@ use usdt::Builder;
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
-    if !version_check::is_min_version("1.59").unwrap_or(false) {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm");
-    }
-    #[cfg(target_os = "macos")]
-    if version_check::supports_feature("asm_sym").unwrap_or(false)
-        && !version_check::is_min_version("1.67").unwrap_or(false)
-    {
-        println!("cargo:rustc-cfg=usdt_need_feat_asm_sym");
-    }
-
     println!("cargo:rerun-if-changed=test.d");
     Builder::new("test.d").build().unwrap();
 }
diff --git a/tests/zero-arg-probe/src/main.rs b/tests/zero-arg-probe/src/main.rs
index e8936f5b..7d2b134f 100644
--- a/tests/zero-arg-probe/src/main.rs
+++ b/tests/zero-arg-probe/src/main.rs
@@ -12,8 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
 #![deny(warnings)]
 
 use usdt::register_probes;
diff --git a/usdt-attr-macro/Cargo.toml b/usdt-attr-macro/Cargo.toml
index 8e01c003..d4acc5ee 100644
--- a/usdt-attr-macro/Cargo.toml
+++ b/usdt-attr-macro/Cargo.toml
@@ -17,9 +17,5 @@ syn = { version = "2", features = ["full"] }
 quote = "1"
 usdt-impl = { path = "../usdt-impl", default-features = false, version = "=0.5.0" }
 
-[features]
-default = ["asm"]
-asm = ["usdt-impl/asm"]
-
 [dev-dependencies]
 rstest = "0.21.0"
diff --git a/usdt-impl/Cargo.toml b/usdt-impl/Cargo.toml
index dfea8f7b..d347c06e 100644
--- a/usdt-impl/Cargo.toml
+++ b/usdt-impl/Cargo.toml
@@ -18,9 +18,6 @@ syn = { version = "2", features = ["full", "extra-traits"] }
 thiserror = "1"
 thread-id = "4"
 
-[build-dependencies]
-version_check = "0.9.5"
-
 [target.'cfg(target_os = "macos")'.dependencies]
 dof = { path = "../dof", optional = true, default-features = false, version = "=0.3.0" }
 
@@ -28,8 +25,7 @@ dof = { path = "../dof", optional = true, default-features = false, version = "=
 dof = { path = "../dof", default-features = false, version = "=0.3.0" }
 
 [features]
-default = ["asm"]
-asm = []
+default = []
 # The `des` feature enables `dof` and company to be able to deserialize special
 # sections emitted in the binary which describe the probes.  Except on
 # platforms with linker integration for USDT probes (currently only MacOS),
diff --git a/usdt-impl/build.rs b/usdt-impl/build.rs
index 67e16249..5ace8226 100644
--- a/usdt-impl/build.rs
+++ b/usdt-impl/build.rs
@@ -28,57 +28,12 @@ enum Backend {
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
-    // `asm` feature was stabilized in 1.59
-    let have_stable_asm = version_check::is_min_version("1.59").unwrap_or(false);
-    // `asm_sym` feature was stabilized in 1.66
-    let have_stable_asm_sym = version_check::is_min_version("1.66").unwrap_or(false);
-
-    // Are we being built with a compiler which allows feature flags (nightly)
-    let is_nightly = version_check::is_feature_flaggable().unwrap_or(false);
-
-    let feat_asm = env::var_os("CARGO_FEATURE_ASM").is_some();
-    let feat_strict_asm = env::var_os("CARGO_FEATURE_STRICT_ASM").is_some();
-
     let backend = match env::var("CARGO_CFG_TARGET_OS").ok().as_deref() {
-        Some("macos") if feat_asm => {
-            if have_stable_asm && have_stable_asm_sym {
-                Backend::Linker
-            } else if feat_strict_asm || is_nightly {
-                if !have_stable_asm {
-                    println!("cargo:rustc-cfg=usdt_need_feat_asm");
-                }
-                if !have_stable_asm_sym {
-                    println!("cargo:rustc-cfg=usdt_need_feat_asm_sym");
-                }
-                Backend::Linker
-            } else {
-                Backend::NoOp
-            }
-        }
-        Some("illumos") | Some("solaris") if feat_asm => {
-            if have_stable_asm {
-                Backend::Standard
-            } else if feat_strict_asm || is_nightly {
-                println!("cargo:rustc-cfg=usdt_need_feat_asm");
-                Backend::Standard
-            } else {
-                Backend::NoOp
-            }
-        }
-        _ => {
-            if !have_stable_asm {
-                println!("cargo:rustc-cfg=usdt_need_feat_asm");
-            }
-            Backend::NoOp
-        }
+        Some("macos") => Backend::Linker,
+        Some("illumos") | Some("solaris") => Backend::Standard,
+        _ => Backend::NoOp,
     };
 
-    // Since visibility of the `asm!()` macro differs between the nightly feature and the
-    // stabilized version, the consumer requires information about its availability
-    if have_stable_asm {
-        println!("cargo:rustc-cfg=usdt_stable_asm");
-    }
-
     match backend {
         Backend::NoOp => {
             println!("cargo:rustc-cfg=usdt_backend_noop");
diff --git a/usdt-impl/src/empty.rs b/usdt-impl/src/empty.rs
index 2423fca6..9c3946df 100644
--- a/usdt-impl/src/empty.rs
+++ b/usdt-impl/src/empty.rs
@@ -1,6 +1,6 @@
 //! The empty implementation of the USDT crate.
 //!
-//! Used when the `asm` feature is disabled, or on platforms without DTrace.
+//! Used on platforms without DTrace.
 
 // Copyright 2021 Oxide Computer Company
 //
diff --git a/usdt-impl/src/lib.rs b/usdt-impl/src/lib.rs
index 7a5decc2..0d035ae3 100644
--- a/usdt-impl/src/lib.rs
+++ b/usdt-impl/src/lib.rs
@@ -14,9 +14,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#![cfg_attr(usdt_need_feat_asm, feature(asm))]
-#![cfg_attr(usdt_need_feat_asm_sym, feature(asm_sym))]
-
 use serde::Deserialize;
 use std::cell::RefCell;
 use thiserror::Error;
diff --git a/usdt-impl/src/linker.rs b/usdt-impl/src/linker.rs
index da75b255..668d7597 100644
--- a/usdt-impl/src/linker.rs
+++ b/usdt-impl/src/linker.rs
@@ -25,7 +25,6 @@
 //!
 //! In rust, we'll want the probe site to look something like this:
 //! ```ignore
-//! #![feature(asm, asm_sym)]
 //! extern "C" {
 //!     #[link_name = "__dtrace_stability$foo$v1$1_1_0_1_1_0_1_1_0_1_1_0_1_1_0"]
 //!     fn stability();
@@ -179,11 +178,6 @@ fn compile_probe(
     #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     compile_error!("USDT only supports x86_64 and AArch64 architectures");
 
-    #[cfg(usdt_stable_asm)]
-    let asm_macro = quote! { std::arch::asm };
-    #[cfg(not(usdt_stable_asm))]
-    let asm_macro = quote! { asm };
-
     let impl_block = quote! {
         extern "C" {
             #[allow(unused)]
@@ -205,7 +199,7 @@ fn compile_probe(
         unsafe {
             if #is_enabled_fn() != 0 {
                 #unpacked_args
-                #asm_macro!(
+                ::std::arch::asm!(
                     ".reference {typedefs}",
                     #call_instruction,
                     ".reference {stability}",
diff --git a/usdt-impl/src/no-linker.rs b/usdt-impl/src/no-linker.rs
index 91d92b33..8c7a00fd 100644
--- a/usdt-impl/src/no-linker.rs
+++ b/usdt-impl/src/no-linker.rs
@@ -82,16 +82,12 @@ fn compile_probe(
     let (unpacked_args, in_regs) = common::construct_probe_args(&probe.types);
     let is_enabled_rec = emit_probe_record(&provider.name, &probe.name, None);
     let probe_rec = emit_probe_record(&provider.name, &probe.name, Some(&probe.types));
-    #[cfg(usdt_stable_asm)]
-    let asm_macro = quote! { std::arch::asm };
-    #[cfg(not(usdt_stable_asm))]
-    let asm_macro = quote! { asm };
 
     let impl_block = quote! {
         {
             let mut is_enabled: u64;
             unsafe {
-                #asm_macro!(
+                ::std::arch::asm!(
                     "990:   clr rax",
                     #is_enabled_rec,
                     out("rax") is_enabled,
@@ -102,7 +98,7 @@ fn compile_probe(
             if is_enabled != 0 {
                 #unpacked_args
                 unsafe {
-                    #asm_macro!(
+                    ::std::arch::asm!(
                         "990:   nop",
                         #probe_rec,
                         #in_regs
diff --git a/usdt-macro/Cargo.toml b/usdt-macro/Cargo.toml
index 6986e2ca..bf358e7b 100644
--- a/usdt-macro/Cargo.toml
+++ b/usdt-macro/Cargo.toml
@@ -14,9 +14,5 @@ syn = { version = "2", features = ["full"] }
 quote = "1"
 usdt-impl = { path = "../usdt-impl", default-features = false, version = "=0.5.0" }
 
-[features]
-default = ["asm"]
-asm = ["usdt-impl/asm"]
-
 [lib]
 proc-macro = true
diff --git a/usdt/Cargo.toml b/usdt/Cargo.toml
index b69c9e5b..04846e1f 100644
--- a/usdt/Cargo.toml
+++ b/usdt/Cargo.toml
@@ -5,7 +5,7 @@ edition = "2021"
 license = "Apache-2.0"
 description = "Dust your Rust with USDT probes"
 repository = "https://github.com/oxidecomputer/usdt.git"
-rust-version = "1.63.0"
+rust-version = "1.75.0"
 
 # NOTE: The use of path and version dependencies is deliberate and load-bearing.
 #
@@ -15,7 +15,6 @@ rust-version = "1.63.0"
 # where the public-facing `usdt` crate may pick up different versions of the
 # internal implementation crates.
 [dependencies]
-dtrace-parser = { path = "../dtrace-parser", optional = true, version = "=0.2.0" }
 serde = "1"
 usdt-impl = { path = "../usdt-impl", default-features = false, version = "=0.5.0", features = [
   "des",
@@ -28,9 +27,9 @@ memmap2 = { version = "0.9.4" }
 
 [features]
 default = ["asm"]
-asm = [
-  "usdt-impl/asm",
-  "usdt-macro/asm",
-  "usdt-attr-macro/asm",
-  "dtrace-parser",
-]
+# This feature used to be functional, but is now a no-op because inline `asm` is available on all
+# supported versions of Rust. It's kept around for BC reasons, but whenever there's a breaking
+# change to the `usdt` crate, this feature should be removed.
+#
+# There's also a comment about this in lib.rs -- remove it when this feature is removed.
+asm = []
diff --git a/usdt/src/lib.rs b/usdt/src/lib.rs
index 07c121bc..c2108397 100644
--- a/usdt/src/lib.rs
+++ b/usdt/src/lib.rs
@@ -275,73 +275,14 @@
 //! purpose. It may be passed as any argument to a probe function, and is guaranteed to be unique
 //! between different invocations of the same probe. See the type's documentation for details.
 //!
-//! Features
-//! --------
+//! About the `asm` feature
+//! -----------------------
+//!
+//! Previous versions of `usdt` used the `asm` feature to enable inline assembly which used to
+//! require nightly Rust with old versions of Rust. Currently, all supported versions of Rust
+//! support inline assembly, and the `asm` feature is a no-op.
 //!
-//! > **Note**: This section is only relevant prior to Rust 1.59 (or Rust 1.66 on macOS).
-//!
-//! The USDT crate relies on inline assembly to hook into DTrace. Prior to Rust 1.59, this is
-//! unstable, and requires explicitly opting in with `#![feature(asm))]`.
-//!
-//! On macOS (only) an additional feature (`asm_sym`) is required prior to Rust 1.66 (but after Rust
-//! 1.58.0-nightly). The macOS implementation relies on native linker support; it uses the `sym`
-//! syntax of the `asm!` macro which was split into its own feature in Rust 1.58.0-nightly
-//! (2021-10-29).
-//!
-//! Unfortunately, because of the way the features were added (see [this pull
-//! request][asm-sym-feature-pr]), this version of Rust nightly is a Rubicon: the `usdt` crate, and
-//! crates using it, _cannot be built with compilers both before and after this version._
-//! Specifically, it's not possible to write the set of features that would allow code to be
-//! compiled with a nightly toolchain before and after this version. If we _include_ the
-//! `feature(asm_sym)` directive with a toolchain of 1.57 or earlier, the compiler will generate an
-//! error because that feature isn't known for those versions. If we _omit_ the directive, it will
-//! compile with previous toolchains, but a newer one will generate an error because the feature is
-//! required for opting into the functionality used in the `usdt` crate's implementation on macOS.
-//!
-//! There's no great solution here. If you're developing an application, i.e., something that you're
-//! sure can be built with a specific toolchain such as with a `rust-toolchain` file, you can write
-//! the correct feature attribute for that toolchain version.
-//!
-//! If you're building a library, things are more complicated, because you don't know what toolchain
-//! a consuming application will choose to use. It's not possible to use a `build.rs` file or other
-//! code-generation mechanism, because inner attributes must generally be written directly at the
-//! top of the crate's root source file. A mechanism that _expands_ to the right tokens is not
-//! sufficient. The only real approach is to specify which versions of the toolchain are supported
-//! by your library in the documentation, as we've done here.
-//!
-//! Selecting the no-op implementation
-//! ----------------------------------
-//!
-//! It's possible to use the `usdt` crate in libraries without transitively requiring a nightly
-//! compiler of one's users (prior to Rust 1.66). Though `asm` is a default feature of the `usdt`
-//! crate, users can opt to build with `--no-default-features`, which uses a no-op implementation of
-//! the internals. This generates the same probe macros, but with empty bodies, meaning the code can
-//! be compiled unchanged.
-//!
-//! Library developers may choose to re-export this feature, with a name such as `probes`, which
-//! implies the `asm` feature of the `usdt` crate. This feature-gating allows users to select a
-//! nightly compiler in exchange for probes, but still allows the code to be compiled with a stable
-//! toolchain.
-//!
-//! Note that prior to Rust 1.66, the appropriate features are required anywhere the generated
-//! macros are _called_, rather than where they're defined. (Because they're macros-by-example, and
-//! expand to an actual `asm!` macro call.) So library writers should probably gate the feature
-//! directive on their own re-exported feature, e.g., `#![cfg_attr(feature = "probes",
-//! feature(asm))]`, and instruct developers consuming their libraries to do the same.
-//!
-//! It's important to keep in mind how Cargo unifies features, however. Specifically, if `usdt` is
-//! a dependency of two other dependencies in a package, it's possible to end up in a confusing
-//! situation. Cargo takes the _union_ of all features in such a case. Thus if one crate is built
-//! expecting to use the no-op implementation and another is built _using_ the real, `asm`-based
-//! implementation, the latter will be chosen. This can be confusing or downright dangerous. First,
-//! the former crate will fail at compile time, because the `asm!` macro will actually be emitted,
-//! but the `#![feature(asm)]` flag will not be included. More troubling, the probes will actually
-//! exist in the resulting object file, even if the user specifically opted to not use them.
-//!
-//! To handle this, library writers may place _all_ references to `usdt`-related code behind a
-//! conditional compilation directive. This will ensure that the crate is not even used, rather
-//! than it being used with an unexpected implementation. This is most relevant for crates whose
-//! minimum supported Rust version is earlier than 1.66.
+//! The next breaking change to `usdt` will remove the `asm` feature entirely.
 //!
 //! [dtrace]: https://illumos.org/books/dtrace/preface.html#preface
 //! [dtrace-usdt]: https://illumos.org/books/dtrace/chp-usdt.html#chp-usdt
@@ -350,7 +291,6 @@
 //! [probe_test_build]: https://github.com/oxidecomputer/usdt/tree/master/probe-test-build
 //! [probe_test_attr]: https://github.com/oxidecomputer/usdt/tree/master/probe-test-attr
 //! [serde]: https://serde.rs
-//! [asm-sym-feature-pr]: https://github.com/rust-lang/rust/pull/90348
 
 use dof::{extract_dof_sections, Section};
 use goblin::Object;