diff --git a/build.zig b/build.zig
index 64afee96..19dcb944 100644
--- a/build.zig
+++ b/build.zig
@@ -56,47 +56,59 @@ pub fn build(b: *std.Build) !void {
         &.{ "/D _CRT_SECURE_NO_WARNINGS", "/WX" }
     else
         &.{"-Wall -Wextra -Werror"};
+    const allocator = std.heap.smp_allocator;
+    var threaded: std.Io.Threaded = .init(allocator, .{
+        .environ = std.process.Environ.empty,
+    });
+
+    const io = threaded.io();
 
     const soem_sources = try globFiles(
         b.path("soem"),
-        std.heap.smp_allocator,
+        allocator,
+        io,
         .{ .extension = "c" },
     );
-    defer std.heap.smp_allocator.free(soem_sources);
+    defer allocator.free(soem_sources);
     const soem_headers = try globFiles(
         b.path("soem"),
-        std.heap.smp_allocator,
+        allocator,
+        io,
         .{ .extension = "h" },
     );
-    defer std.heap.smp_allocator.free(soem_headers);
+    defer allocator.free(soem_headers);
 
     const osal_path = b.path("osal").path(b, os_subdir);
     const osal_sources = try globFiles(
         osal_path,
-        std.heap.smp_allocator,
+        allocator,
+        io,
         .{ .extension = "c" },
     );
-    defer std.heap.smp_allocator.free(osal_sources);
+    defer allocator.free(osal_sources);
     const osal_headers = try globFiles(
         osal_path,
-        std.heap.smp_allocator,
+        allocator,
+        io,
         .{ .extension = "h" },
     );
-    defer std.heap.smp_allocator.free(osal_headers);
+    defer allocator.free(osal_headers);
 
     const oshw_path = b.path("oshw").path(b, os_subdir);
     const oshw_sources = try globFiles(
         oshw_path,
-        std.heap.smp_allocator,
+        allocator,
+        io,
         .{ .extension = "c" },
     );
-    defer std.heap.smp_allocator.free(oshw_sources);
+    defer allocator.free(oshw_sources);
     const oshw_headers = try globFiles(
         oshw_path,
-        std.heap.smp_allocator,
+        allocator,
+        io,
         .{ .extension = "h" },
     );
-    defer std.heap.smp_allocator.free(oshw_headers);
+    defer allocator.free(oshw_headers);
 
     lib_mod.addCSourceFiles(.{
         .root = b.path("soem"),
@@ -179,12 +191,12 @@ const GlobOptions = struct {
     recursive: bool = false,
 };
 
-fn countFiles(dir: std.fs.Dir, options: GlobOptions) !usize {
+fn countFiles(io: std.Io, dir: std.Io.Dir, options: GlobOptions) !usize {
     var walker = dir.iterate();
     var total_count: usize = 0;
 
     // Walk once to get total file count.
-    while (try walker.next()) |entry| {
+    while (try walker.next(io)) |entry| {
         if (entry.kind == .file) {
             if (options.extension.len > 0) {
                 const extension =
@@ -197,9 +209,9 @@ fn countFiles(dir: std.fs.Dir, options: GlobOptions) !usize {
                 total_count += 1;
             }
         } else if (entry.kind == .directory and options.recursive) {
-            var sub_dir = try dir.openDir(entry.name, .{ .iterate = true });
-            defer sub_dir.close();
-            total_count += try countFiles(sub_dir, options);
+            var sub_dir = try dir.openDir(io, entry.name, .{ .iterate = true });
+            defer sub_dir.close(io);
+            total_count += try countFiles(io, sub_dir, options);
         }
     }
 
@@ -207,7 +219,8 @@ fn countFiles(dir: std.fs.Dir, options: GlobOptions) !usize {
 }
 
 fn globInner(
-    dir: std.fs.Dir,
+    io: std.Io,
+    dir: std.Io.Dir,
     allocator: std.mem.Allocator,
     results: [][]u8,
     filled_: usize,
@@ -217,7 +230,7 @@ fn globInner(
     var filled = filled_;
 
     // Walk once to get total file count.
-    while (try walker.next()) |entry| {
+    while (try walker.next(io)) |entry| {
         if (entry.kind == .file) {
             if (options.extension.len > 0) {
                 const extension =
@@ -232,10 +245,10 @@ fn globInner(
                 filled += 1;
             }
         } else if (entry.kind == .directory and options.recursive) {
-            var sub_dir = try dir.openDir(entry.name, .{ .iterate = true });
-            defer sub_dir.close();
+            var sub_dir = try dir.openDir(io, entry.name, .{ .iterate = true });
+            defer sub_dir.close(io);
 
-            try globInner(sub_dir, allocator, results, filled, options);
+            try globInner(io, sub_dir, allocator, results, filled, options);
         }
     }
 }
@@ -243,29 +256,32 @@ fn globInner(
 fn globFiles(
     path: std.Build.LazyPath,
     allocator: std.mem.Allocator,
+    io: std.Io,
     options: GlobOptions,
 ) ![]const []const u8 {
     var dir = switch (path) {
-        .cwd_relative => try std.fs.cwd().openDir(
+        .cwd_relative => try std.Io.Dir.cwd().openDir(
+            io,
             path.src_path.sub_path,
             .{ .iterate = true },
         ),
         .src_path => |sp| try sp.owner.build_root.handle.openDir(
+            io,
             sp.sub_path,
             .{ .iterate = true },
         ),
         else => unreachable,
     };
-    defer dir.close();
+    defer dir.close(io);
 
-    const total_count = try countFiles(dir, options);
+    const total_count = try countFiles(io, dir, options);
 
     const result: [][]u8 = try allocator.alloc([]u8, total_count);
     for (result) |*file| {
         file.* = &.{};
     }
 
-    try globInner(dir, allocator, result, 0, options);
+    try globInner(io, dir, allocator, result, 0, options);
 
     return result;
 }
diff --git a/build.zig.zon b/build.zig.zon
index 4e0184b8..779ddaa2 100644
--- a/build.zig.zon
+++ b/build.zig.zon
@@ -1,7 +1,7 @@
 .{
     .name = .soem,
     .fingerprint = 0x30ccde7443fac184,
-    .minimum_zig_version = "0.14.0",
+    .minimum_zig_version = "0.16.0-dev.2187+e2338edb4",
     .version = "1.4.0",
     .paths = .{
         "soem",