diff --git a/inst/include/cpp11.hpp b/inst/include/cpp11.hpp
index 550f23166..00b8d163b 100644
--- a/inst/include/cpp11.hpp
+++ b/inst/include/cpp11.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include "cpp11/R.hpp"
diff --git a/inst/include/cpp11/R.hpp b/inst/include/cpp11/R.hpp
index 5579a8c94..982b42e63 100644
--- a/inst/include/cpp11/R.hpp
+++ b/inst/include/cpp11/R.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #ifdef R_INTERNALS_H_
@@ -13,9 +13,11 @@
 #ifndef R_NO_REMAP
 #define R_NO_REMAP
 #endif
+
 #ifndef STRICT_R_HEADERS
 #define STRICT_R_HEADERS
 #endif
+
 #include "R_ext/Boolean.h"
 #include "Rinternals.h"
 #include "Rversion.h"
@@ -33,7 +35,6 @@
 // clang-format on
 
 #include <type_traits>
-#include "cpp11/altrep.hpp"
 
 #if defined(R_VERSION) && R_VERSION >= R_Version(4, 4, 0)
 // Use R's new macro
diff --git a/inst/include/cpp11/altrep.hpp b/inst/include/cpp11/altrep.hpp
index 12bc0916c..0d16e7be6 100644
--- a/inst/include/cpp11/altrep.hpp
+++ b/inst/include/cpp11/altrep.hpp
@@ -1,44 +1,8 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
-#include "Rversion.h"
-
-#if defined(R_VERSION) && R_VERSION >= R_Version(3, 5, 0)
+// It would be nice to remove this since all supported versions of R have ALTREP, but
+// some groups rely on both this `#define` and `altrep.hpp` itself existing, like arrow:
+// https://github.com/r-lib/cpp11/issues/413
 #define HAS_ALTREP
-#endif
-
-#ifndef HAS_ALTREP
-
-#define ALTREP(x) false
-
-#define REAL_ELT(x, i) REAL(x)[i]
-#define INTEGER_ELT(x, i) INTEGER(x)[i]
-#define LOGICAL_ELT(x, i) LOGICAL(x)[i]
-#define RAW_ELT(x, i) RAW(x)[i]
-
-#define SET_REAL_ELT(x, i, val) REAL(x)[i] = val
-#define SET_INTEGER_ELT(x, i, val) INTEGER(x)[i] = val
-#define SET_LOGICAL_ELT(x, i, val) LOGICAL(x)[i] = val
-#define SET_RAW_ELT(x, i, val) RAW(x)[i] = val
-
-#define REAL_GET_REGION(...) \
-  do {                       \
-  } while (false)
-
-#define INTEGER_GET_REGION(...) \
-  do {                          \
-  } while (false)
-#endif
-
-#if !defined HAS_ALTREP || (defined(R_VERSION) && R_VERSION < R_Version(3, 6, 0))
-
-#define LOGICAL_GET_REGION(...) \
-  do {                          \
-  } while (false)
-
-#define RAW_GET_REGION(...) \
-  do {                      \
-  } while (false)
-
-#endif
diff --git a/inst/include/cpp11/as.hpp b/inst/include/cpp11/as.hpp
index 12ef05838..9152e5864 100644
--- a/inst/include/cpp11/as.hpp
+++ b/inst/include/cpp11/as.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <cmath>             // for modf
diff --git a/inst/include/cpp11/attribute_proxy.hpp b/inst/include/cpp11/attribute_proxy.hpp
index 31e029147..276ee8d33 100644
--- a/inst/include/cpp11/attribute_proxy.hpp
+++ b/inst/include/cpp11/attribute_proxy.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <initializer_list>  // for initializer_list
diff --git a/inst/include/cpp11/data_frame.hpp b/inst/include/cpp11/data_frame.hpp
index d5376e7d5..73143a2ca 100644
--- a/inst/include/cpp11/data_frame.hpp
+++ b/inst/include/cpp11/data_frame.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <cstdlib>  // for abs
diff --git a/inst/include/cpp11/declarations.hpp b/inst/include/cpp11/declarations.hpp
index d94afa39d..7aa879f19 100644
--- a/inst/include/cpp11/declarations.hpp
+++ b/inst/include/cpp11/declarations.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <cstring>
@@ -32,13 +32,10 @@ T& unmove(T&& t) {
 }
 }  // namespace cpp11
 
-#ifdef HAS_UNWIND_PROTECT
+// We would like to remove this, since all supported versions of R now support proper
+// unwind protect, but some groups rely on it existing, like textshaping:
+// https://github.com/r-lib/cpp11/issues/414
 #define CPP11_UNWIND R_ContinueUnwind(err);
-#else
-#define CPP11_UNWIND \
-  do {               \
-  } while (false);
-#endif
 
 #define CPP11_ERROR_BUFSIZE 8192
 
@@ -60,7 +57,7 @@ T& unmove(T&& t) {
   if (buf[0] != '\0') {                                         \
     Rf_errorcall(R_NilValue, "%s", buf);                        \
   } else if (err != R_NilValue) {                               \
-    CPP11_UNWIND                                                \
+    R_ContinueUnwind(err);                                      \
   }                                                             \
   return RET;
 #define END_CPP11 END_CPP11_EX(R_NilValue)
diff --git a/inst/include/cpp11/doubles.hpp b/inst/include/cpp11/doubles.hpp
index 8495f28fc..f8b2f64fa 100644
--- a/inst/include/cpp11/doubles.hpp
+++ b/inst/include/cpp11/doubles.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <algorithm>         // for min, tranform
@@ -50,7 +50,7 @@ inline void r_vector<double>::get_region(SEXP x, R_xlen_t i, R_xlen_t n,
                                          typename r_vector::underlying_type* buf) {
   // NOPROTECT: likely too costly to unwind protect here
   REAL_GET_REGION(x, i, n, buf);
-};
+}
 
 template <>
 inline bool r_vector<double>::const_iterator::use_buf(bool is_altrep) {
diff --git a/inst/include/cpp11/environment.hpp b/inst/include/cpp11/environment.hpp
index b8e96d67b..23f54f9ce 100644
--- a/inst/include/cpp11/environment.hpp
+++ b/inst/include/cpp11/environment.hpp
@@ -1,23 +1,14 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <string>  // for string, basic_string
 
-#include "Rversion.h"         // for R_VERSION, R_Version
 #include "cpp11/R.hpp"        // for SEXP, SEXPREC, Rf_install, r_env_get...
 #include "cpp11/as.hpp"       // for as_sexp
 #include "cpp11/protect.hpp"  // for protect, protect::function, safe, unwin...
 #include "cpp11/sexp.hpp"     // for sexp
 
-#if R_VERSION >= R_Version(4, 0, 0)
-#define HAS_REMOVE_VAR_FROM_FRAME
-#endif
-
-#ifndef HAS_REMOVE_VAR_FROM_FRAME
-#include "cpp11/function.hpp"
-#endif
-
 namespace cpp11 {
 
 class environment {
@@ -53,12 +44,7 @@ class environment {
 
   void remove(SEXP name) {
     PROTECT(name);
-#ifdef HAS_REMOVE_VAR_FROM_FRAME
     R_removeVarFromFrame(name, env_);
-#else
-    auto remove = package("base")["remove"];
-    remove(name, "envir"_nm = env_);
-#endif
     UNPROTECT(1);
   }
 
diff --git a/inst/include/cpp11/external_pointer.hpp b/inst/include/cpp11/external_pointer.hpp
index 070433a33..e441bc0f8 100644
--- a/inst/include/cpp11/external_pointer.hpp
+++ b/inst/include/cpp11/external_pointer.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <cstddef>      // for nullptr_t, NULL
@@ -57,7 +57,8 @@ class external_pointer {
 
   external_pointer(SEXP data) : data_(valid_type(data)) {}
 
-  external_pointer(pointer p, bool use_deleter = true, bool finalize_on_exit = true, SEXP prot = R_NilValue)
+  external_pointer(pointer p, bool use_deleter = true, bool finalize_on_exit = true,
+                   SEXP prot = R_NilValue)
       : data_(safe[R_MakeExternalPtr]((void*)p, R_NilValue, prot)) {
     if (use_deleter) {
       R_RegisterCFinalizerEx(data_, r_deleter, static_cast<r_bool>(finalize_on_exit));
diff --git a/inst/include/cpp11/function.hpp b/inst/include/cpp11/function.hpp
index c719a9639..23a646cba 100644
--- a/inst/include/cpp11/function.hpp
+++ b/inst/include/cpp11/function.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <string.h>  // for strcmp
diff --git a/inst/include/cpp11/integers.hpp b/inst/include/cpp11/integers.hpp
index 53145e795..ca4261be6 100644
--- a/inst/include/cpp11/integers.hpp
+++ b/inst/include/cpp11/integers.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <algorithm>         // for min
@@ -51,7 +51,7 @@ inline void r_vector<int>::get_region(SEXP x, R_xlen_t i, R_xlen_t n,
                                       typename r_vector::underlying_type* buf) {
   // NOPROTECT: likely too costly to unwind protect here
   INTEGER_GET_REGION(x, i, n, buf);
-};
+}
 
 template <>
 inline bool r_vector<int>::const_iterator::use_buf(bool is_altrep) {
diff --git a/inst/include/cpp11/list.hpp b/inst/include/cpp11/list.hpp
index 91cae6f33..9df36cf7e 100644
--- a/inst/include/cpp11/list.hpp
+++ b/inst/include/cpp11/list.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <initializer_list>  // for initializer_list
@@ -54,7 +54,7 @@ template <>
 inline void r_vector<SEXP>::get_region(SEXP x, R_xlen_t i, R_xlen_t n,
                                        typename r_vector::underlying_type* buf) {
   cpp11::stop("Unreachable!");
-};
+}
 
 template <>
 inline bool r_vector<SEXP>::const_iterator::use_buf(bool is_altrep) {
diff --git a/inst/include/cpp11/list_of.hpp b/inst/include/cpp11/list_of.hpp
index 8ba15800a..979a338df 100644
--- a/inst/include/cpp11/list_of.hpp
+++ b/inst/include/cpp11/list_of.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <string>  // for string, basic_string
diff --git a/inst/include/cpp11/logicals.hpp b/inst/include/cpp11/logicals.hpp
index 25806d253..e834482b5 100644
--- a/inst/include/cpp11/logicals.hpp
+++ b/inst/include/cpp11/logicals.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <algorithm>         // for min
@@ -50,7 +50,7 @@ inline void r_vector<r_bool>::get_region(SEXP x, R_xlen_t i, R_xlen_t n,
                                          typename r_vector::underlying_type* buf) {
   // NOPROTECT: likely too costly to unwind protect here
   LOGICAL_GET_REGION(x, i, n, buf);
-};
+}
 
 template <>
 inline bool r_vector<r_bool>::const_iterator::use_buf(bool is_altrep) {
diff --git a/inst/include/cpp11/matrix.hpp b/inst/include/cpp11/matrix.hpp
index d69c26ebc..0d53143ef 100644
--- a/inst/include/cpp11/matrix.hpp
+++ b/inst/include/cpp11/matrix.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <iterator>
diff --git a/inst/include/cpp11/named_arg.hpp b/inst/include/cpp11/named_arg.hpp
index c033d54aa..2614e6959 100644
--- a/inst/include/cpp11/named_arg.hpp
+++ b/inst/include/cpp11/named_arg.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <stddef.h>  // for size_t
diff --git a/inst/include/cpp11/protect.hpp b/inst/include/cpp11/protect.hpp
index 2d6093b0c..b30d95c45 100644
--- a/inst/include/cpp11/protect.hpp
+++ b/inst/include/cpp11/protect.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <csetjmp>    // for longjmp, setjmp, jmp_buf
@@ -15,11 +15,11 @@
 #include "R_ext/Error.h"    // for Rf_error, Rf_warning
 #include "R_ext/Print.h"    // for REprintf
 #include "R_ext/Utils.h"    // for R_CheckUserInterrupt
-#include "Rversion.h"       // for R_VERSION, R_Version
 
-#if defined(R_VERSION) && R_VERSION >= R_Version(3, 5, 0)
+// We would like to remove this, since all supported versions of R now support proper
+// unwind protect, but some groups rely on it existing, like arrow and systemfonts
+// https://github.com/r-lib/cpp11/issues/412
 #define HAS_UNWIND_PROTECT
-#endif
 
 #ifdef CPP11_USE_FMT
 #define FMT_HEADER_ONLY
@@ -33,8 +33,6 @@ class unwind_exception : public std::exception {
   unwind_exception(SEXP token_) : token(token_) {}
 };
 
-#ifdef HAS_UNWIND_PROTECT
-
 /// Unwind Protection from C longjmp's, like those used in R error handling
 ///
 /// @param code The code to which needs to be protected, as a nullary callable
@@ -97,15 +95,6 @@ unwind_protect(Fun&& code) {
   return out;
 }
 
-#else
-// Don't do anything if we don't have unwind protect. This will leak C++ resources,
-// including those held by cpp11 objects, but the other alternatives are also not great.
-template <typename Fun>
-decltype(std::declval<Fun&&>()()) unwind_protect(Fun&& code) {
-  return std::forward<Fun>(code)();
-}
-#endif
-
 namespace detail {
 
 template <size_t...>
diff --git a/inst/include/cpp11/r_bool.hpp b/inst/include/cpp11/r_bool.hpp
index eb2b1eda7..a66e77dc1 100644
--- a/inst/include/cpp11/r_bool.hpp
+++ b/inst/include/cpp11/r_bool.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <limits>  // for numeric_limits
diff --git a/inst/include/cpp11/r_string.hpp b/inst/include/cpp11/r_string.hpp
index 63dbafb9f..25022aa7b 100644
--- a/inst/include/cpp11/r_string.hpp
+++ b/inst/include/cpp11/r_string.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <string>       // for string, basic_string, operator==
diff --git a/inst/include/cpp11/r_vector.hpp b/inst/include/cpp11/r_vector.hpp
index 637981d33..a9848596b 100644
--- a/inst/include/cpp11/r_vector.hpp
+++ b/inst/include/cpp11/r_vector.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <stddef.h>  // for ptrdiff_t, size_t
@@ -422,7 +422,7 @@ inline r_vector<T>& r_vector<T>::operator=(const r_vector& rhs) {
   length_ = rhs.length_;
 
   return *this;
-};
+}
 
 // Same reasoning as `r_vector(r_vector&& x)` constructor
 template <typename T>
@@ -448,7 +448,7 @@ inline r_vector<T>& r_vector<T>::operator=(r_vector&& rhs) {
   rhs.length_ = 0;
 
   return *this;
-};
+}
 
 template <typename T>
 inline r_vector<T>::operator SEXP() const {
@@ -1325,7 +1325,8 @@ inline SEXP r_vector<T>::reserve_data(SEXP x, bool is_altrep, R_xlen_t size) {
   SEXP out = PROTECT(resize_data(x, is_altrep, size));
 
   // Resize names, if required
-  SEXP names = Rf_getAttrib(x, R_NamesSymbol);
+  // Protection seems needed to make rchk happy
+  SEXP names = PROTECT(Rf_getAttrib(x, R_NamesSymbol));
   if (names != R_NilValue) {
     if (Rf_xlength(names) != size) {
       names = resize_names(names, size);
@@ -1340,7 +1341,7 @@ inline SEXP r_vector<T>::reserve_data(SEXP x, bool is_altrep, R_xlen_t size) {
   // Does not look like it would ever error in our use cases, so no `safe[]`.
   Rf_copyMostAttrib(x, out);
 
-  UNPROTECT(1);
+  UNPROTECT(2);
   return out;
 }
 
diff --git a/inst/include/cpp11/raws.hpp b/inst/include/cpp11/raws.hpp
index ba152a5ba..218b4bb90 100644
--- a/inst/include/cpp11/raws.hpp
+++ b/inst/include/cpp11/raws.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <algorithm>         // for min
@@ -58,7 +58,7 @@ inline void r_vector<uint8_t>::get_region(SEXP x, R_xlen_t i, R_xlen_t n,
                                           typename r_vector::underlying_type* buf) {
   // NOPROTECT: likely too costly to unwind protect here
   RAW_GET_REGION(x, i, n, buf);
-};
+}
 
 template <>
 inline bool r_vector<uint8_t>::const_iterator::use_buf(bool is_altrep) {
diff --git a/inst/include/cpp11/sexp.hpp b/inst/include/cpp11/sexp.hpp
index b8d24dac1..aceeff3fc 100644
--- a/inst/include/cpp11/sexp.hpp
+++ b/inst/include/cpp11/sexp.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <stddef.h>  // for size_t
diff --git a/inst/include/cpp11/strings.hpp b/inst/include/cpp11/strings.hpp
index a39859783..c72d25b8f 100644
--- a/inst/include/cpp11/strings.hpp
+++ b/inst/include/cpp11/strings.hpp
@@ -1,5 +1,5 @@
-// cpp11 version: 0.5.0
-// vendored on: 2024-09-24
+// cpp11 version: 0.5.1
+// vendored on: 2024-12-07
 #pragma once
 
 #include <initializer_list>  // for initializer_list
@@ -51,7 +51,7 @@ template <>
 inline void r_vector<r_string>::get_region(SEXP x, R_xlen_t i, R_xlen_t n,
                                            typename r_vector::underlying_type* buf) {
   cpp11::stop("Unreachable!");
-};
+}
 
 template <>
 inline bool r_vector<r_string>::const_iterator::use_buf(bool is_altrep) {