diff --git a/.evergreen/config_generator/components/funcs/install_c_driver.py b/.evergreen/config_generator/components/funcs/install_c_driver.py
index 29e886d159..fe81f5920e 100644
--- a/.evergreen/config_generator/components/funcs/install_c_driver.py
+++ b/.evergreen/config_generator/components/funcs/install_c_driver.py
@@ -14,7 +14,7 @@
 # Only LIBMONGOC_DOWNLOAD_VERSION needs to be updated when pinning to an unreleased commit.
 # If pinning to an unreleased commit, create a "Blocked" JIRA ticket with
 # a "depends on" link to the appropriate C Driver version release ticket.
-MONGOC_VERSION_MINIMUM = '1.30.1'
+MONGOC_VERSION_MINIMUM = '57bffac11fde38d1ce097bb22fb5322a6114d644' # CXX-3103: bump to 2.0.0 once released.
 
 
 class InstallCDriver(Function):
diff --git a/.evergreen/generated_configs/functions.yml b/.evergreen/generated_configs/functions.yml
index c3448b6d91..783a6148bd 100644
--- a/.evergreen/generated_configs/functions.yml
+++ b/.evergreen/generated_configs/functions.yml
@@ -398,7 +398,7 @@ functions:
       type: setup
       params:
         updates:
-          - { key: mongoc_version_minimum, value: 1.30.1 }
+          - { key: mongoc_version_minimum, value: 57bffac11fde38d1ce097bb22fb5322a6114d644 }
     - command: subprocess.exec
       type: setup
       params:
diff --git a/.evergreen/scripts/install-c-driver.sh b/.evergreen/scripts/install-c-driver.sh
index 0a176e8594..073ffb88db 100755
--- a/.evergreen/scripts/install-c-driver.sh
+++ b/.evergreen/scripts/install-c-driver.sh
@@ -40,6 +40,9 @@ tar xzf mongo-c-driver.tar.gz --directory "${mongoc_dir}" --strip-components=1
 # C Driver needs VERSION_CURRENT to compute BUILD_VERSION.
 if [[ -f "${mongoc_dir}/VERSION_CURRENT" ]]; then
   : # Use the existing VERSION_CURRENT bundled with the release tarball.
+
+  # CXX-3103: overwrite incompatible build versions to support the upcoming 2.0.0 release.
+  echo "1.31.0-pre" >|"${mongoc_dir}/VERSION_CURRENT"
 else
   # RegEx pattern to match SemVer strings. See https://semver.org/.
   declare -r semver_regex="^(?P<major>0|[1-9]\d*)\.(?P<minor>0|[1-9]\d*)\.(?P<patch>0|[1-9]\d*)(?:-(?P<prerelease>(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+(?P<buildmetadata>[0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$"
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 88c466f985..63cf82378d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -54,7 +54,7 @@ set(LIBBSON_REQUIRED_ABI_VERSION 1.0)
 
 # Also update etc/purls.txt.
 set(LIBMONGOC_REQUIRED_VERSION 1.30.0)
-set(LIBMONGOC_DOWNLOAD_VERSION 1.30.1)
+set(LIBMONGOC_DOWNLOAD_VERSION 57bffac11fde38d1ce097bb22fb5322a6114d644)
 set(LIBMONGOC_REQUIRED_ABI_VERSION 1.0)
 
 set(NEED_DOWNLOAD_C_DRIVER false)
diff --git a/examples/api/bsoncxx/examples/bson_errors/big_string.hh b/examples/api/bsoncxx/examples/bson_errors/big_string.hh
index d8d14af18e..35d0eecd66 100644
--- a/examples/api/bsoncxx/examples/bson_errors/big_string.hh
+++ b/examples/api/bsoncxx/examples/bson_errors/big_string.hh
@@ -27,8 +27,7 @@ namespace examples {
 // Used to trigger builder append failure.
 struct big_string {
     // BSON_SIZE_MAX == 0x7FFFFFFF
-    // Leave some room for CDRIVER-5732.
-    std::size_t length{static_cast<std::size_t>(std::numeric_limits<std::int32_t>::max() - 32u)};
+    std::size_t length{static_cast<std::size_t>(std::numeric_limits<std::int32_t>::max())};
 
     // Allocate an UNINITIALIZED blob of data that will not be accessed due to length checks.
     // Leaving memory unitialized (rather than zero-init) should hopefully avoid slow and expensive
diff --git a/src/bsoncxx/lib/bsoncxx/v_noabi/bsoncxx/builder/core.cpp b/src/bsoncxx/lib/bsoncxx/v_noabi/bsoncxx/builder/core.cpp
index 1b06149488..3d7f070d76 100644
--- a/src/bsoncxx/lib/bsoncxx/v_noabi/bsoncxx/builder/core.cpp
+++ b/src/bsoncxx/lib/bsoncxx/v_noabi/bsoncxx/builder/core.cpp
@@ -298,13 +298,14 @@ core& core::append(types::b_double const& value) {
 
 core& core::append(types::b_string const& value) {
     stdx::string_view key = _impl->next_key();
-
-    if (!bson_append_utf8(
-            _impl->back(),
-            key.data(),
-            static_cast<std::int32_t>(key.length()),
-            value.value.data(),
-            static_cast<std::int32_t>(value.value.length()))) {
+    std::size_t value_length = value.value.length();
+
+    if (value_length > std::size_t{INT32_MAX} || !bson_append_utf8(
+                                                     _impl->back(),
+                                                     key.data(),
+                                                     static_cast<std::int32_t>(key.length()),
+                                                     value.value.data(),
+                                                     static_cast<std::int32_t>(value_length))) {
         throw bsoncxx::v_noabi::exception{error_code::k_cannot_append_string};
     }