diff --git a/.gitignore b/.gitignore
index 3236373..d252b85 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,4 +10,6 @@
 !go.sum
 !*.md
 !*.go
-!*.py
\ No newline at end of file
+!*.py
+!*.lock
+!*.nix
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..897df41
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1701680307,
+        "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "4022d587cbbfd70fe950c1e2083a02621806a725",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1703438236,
+        "narHash": "sha256-aqVBq1u09yFhL7bj1/xyUeJjzr92fXVvQSSEx6AdB1M=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "5f64a12a728902226210bf01d25ec6cbb9d9265b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..1063b87
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,22 @@
+{
+  description = "A flake that sets up the devShell";
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    let supportedSystems = [ "aarch64-linux" "i686-linux" "x86_64-linux" ];
+    in flake-utils.lib.eachSystem supportedSystems (system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [ ];
+        };
+        pp = ps: with ps; [ regex ];
+      in {
+        devShell = pkgs.mkShell {
+          buildInputs = with pkgs; [ go (python312.withPackages pp) ];
+        };
+      });
+}
diff --git a/testdata/gendata.py b/testdata/gendata.py
index 1f07482..7059f24 100644
--- a/testdata/gendata.py
+++ b/testdata/gendata.py
@@ -1,6 +1,7 @@
 # This script generates testdata for particular version of unicode.
 # Used Python 3.8.7 && regex==2020.2.20 to generate cases for unicode 12.1.0.
 # Used Python 3.9.1 && regex>2020.2.20 to generate cases for unicode 13.0.0.
+# Used Python 3.12.1 && regex==2023.8.8 to generate cases for unicode 15.0.0.
 
 import unicodedata
 import regex
@@ -10,7 +11,7 @@
 def gendata(category):
     f = gzip.open(f'{category}{unicodedata.unidata_version}.txt.gz', 'wb')
     for r in range(sys.maxunicode+1):
-        matched = bool(regex.match(f'\p{{{category}}}', chr(r)))
+        matched = bool(regex.match(f'\\p{{{category}}}', chr(r)))
         if matched:
             f.write(b'T')
         else:
diff --git a/testdata/xid_continue15.0.0.txt.gz b/testdata/xid_continue15.0.0.txt.gz
new file mode 100644
index 0000000..c353c23
Binary files /dev/null and b/testdata/xid_continue15.0.0.txt.gz differ
diff --git a/testdata/xid_start15.0.0.txt.gz b/testdata/xid_start15.0.0.txt.gz
new file mode 100644
index 0000000..b23f3d8
Binary files /dev/null and b/testdata/xid_start15.0.0.txt.gz differ
diff --git a/unicodeTestVersion_114.go b/unicodeTestVersion_114.go
index b28670f..1060aeb 100644
--- a/unicodeTestVersion_114.go
+++ b/unicodeTestVersion_114.go
@@ -1,3 +1,4 @@
+//go:build go1.14 && !go1.16
 // +build go1.14,!go1.16
 
 package xid
diff --git a/unicodeTestVersion_116.go b/unicodeTestVersion_116.go
index 7372553..fc77c35 100644
--- a/unicodeTestVersion_116.go
+++ b/unicodeTestVersion_116.go
@@ -1,4 +1,5 @@
-// +build go1.16
+//go:build go1.16 && !go1.21
+// +build go1.16,!go1.21
 
 package xid
 
diff --git a/unicodeTestVersion_121.go b/unicodeTestVersion_121.go
new file mode 100644
index 0000000..bbe777f
--- /dev/null
+++ b/unicodeTestVersion_121.go
@@ -0,0 +1,6 @@
+//go:build go1.21
+// +build go1.21
+
+package xid
+
+const unicodeTestVersion = "15.0.0"