diff --git a/.github/workflows/puma.yml b/.github/workflows/puma.yml
index b669918573..9efb9de46a 100644
--- a/.github/workflows/puma.yml
+++ b/.github/workflows/puma.yml
@@ -19,16 +19,16 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ ubuntu-20.04, ubuntu-18.04, macos-10.15, windows-2019 ]
-        ruby: [ 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, head ]
+        os: [ ubuntu-20.04, ubuntu-18.04, macos-10.15, windows-2022 ]
+        ruby: [ 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, '3.0', 3.1, head ]
         include:
-          - { os: windows-2019 , ruby: mingw }
+          - { os: windows-2022 , ruby: ucrt }
         exclude:
           - { os: ubuntu-20.04 , ruby: 2.2 }
           - { os: ubuntu-20.04 , ruby: 2.3 }
           - { os: ubuntu-20.04 , ruby: 2.4 }
           - { os: ubuntu-20.04 , ruby: 2.6 }
-          - { os: windows-2019 , ruby: head }
+          - { os: windows-2022 , ruby: head }
 
     steps:
       - name: repo checkout
@@ -40,7 +40,7 @@ jobs:
           ruby-version: ${{ matrix.ruby }}
           apt-get: ragel
           brew: ragel
-          mingw: _upgrade_ openssl ragel
+          mingw: openssl ragel
 
       - name:  bundle install
         shell: pwsh
diff --git a/.gitignore b/.gitignore
index 65ab3826cf..1051bb4b61 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,6 +11,7 @@ pkg
 tmp
 t/
 .rbx/
+vendor/
 Gemfile.lock
 .idea/
 /test/test_puma.state
diff --git a/ext/puma_http11/extconf.rb b/ext/puma_http11/extconf.rb
index feb812d8a6..524a992de7 100644
--- a/ext/puma_http11/extconf.rb
+++ b/ext/puma_http11/extconf.rb
@@ -22,6 +22,14 @@
     # with versions after 1.1.1
     have_func  "TLS_server_method"            , "openssl/ssl.h"
     have_macro "SSL_CTX_set_min_proto_version", "openssl/ssl.h"
+
+    # Random.bytes available in Ruby 2.5 and later, Random::DEFAULT deprecated in 3.0
+    if Random.respond_to?(:bytes)
+      $defs.push("-DHAVE_RANDOM_BYTES")
+      puts "checking for Random.bytes... yes"
+    else
+      puts "checking for Random.bytes... no"
+    end
   end
 end
 
diff --git a/ext/puma_http11/mini_ssl.c b/ext/puma_http11/mini_ssl.c
index 6312c60ba4..eaa7baca81 100644
--- a/ext/puma_http11/mini_ssl.c
+++ b/ext/puma_http11/mini_ssl.c
@@ -62,44 +62,65 @@ ms_conn* engine_alloc(VALUE klass, VALUE* obj) {
   return conn;
 }
 
-DH *get_dh1024() {
-  /* `openssl dhparam 1024 -C`
+DH *get_dh2048(void) {
+  /* `openssl dhparam -C 2048`
    * -----BEGIN DH PARAMETERS-----
-   * MIGHAoGBALPwcEv0OstmQCZdfHw0N5r+07lmXMxkpQacy1blwj0LUqC+Divp6pBk
-   * usTJ9W2/dOYr1X7zi6yXNLp4oLzc/31PUL3D9q8CpGS7vPz5gijKSw9BwCTT5z9+
-   * KF9v46qw8XqT5HHV87sWFlGQcVFq+pEkA2kPikkKZ/X/CCcpCAV7AgEC
+   * MIIBCAKCAQEAjmh1uQHdTfxOyxEbKAV30fUfzqMDF/ChPzjfyzl2jcrqQMhrk76o
+   * 2NPNXqxHwsddMZ1RzvU8/jl+uhRuPWjXCFZbhET4N1vrviZM3VJhV8PPHuiVOACO
+   * y32jFd+Szx4bo2cXSK83hJ6jRd+0asP1awWjz9/06dFkrILCXMIfQLo0D8rqmppn
+   * EfDDAwuudCpM9kcDmBRAm9JsKbQ6gzZWjkc5+QWSaQofojIHbjvj3xzguaCJn+oQ
+   * vHWM+hsAnaOgEwCyeZ3xqs+/5lwSbkE/tqJW98cEZGygBUVo9jxZRZx6KOfjpdrb
+   * yenO9LJr/qtyrZB31WJbqxI0m0AKTAO8UwIBAg==
    * -----END DH PARAMETERS-----
    */
-  static unsigned char dh1024_p[] = {
-    0xB3,0xF0,0x70,0x4B,0xF4,0x3A,0xCB,0x66,0x40,0x26,0x5D,0x7C,
-    0x7C,0x34,0x37,0x9A,0xFE,0xD3,0xB9,0x66,0x5C,0xCC,0x64,0xA5,
-    0x06,0x9C,0xCB,0x56,0xE5,0xC2,0x3D,0x0B,0x52,0xA0,0xBE,0x0E,
-    0x2B,0xE9,0xEA,0x90,0x64,0xBA,0xC4,0xC9,0xF5,0x6D,0xBF,0x74,
-    0xE6,0x2B,0xD5,0x7E,0xF3,0x8B,0xAC,0x97,0x34,0xBA,0x78,0xA0,
-    0xBC,0xDC,0xFF,0x7D,0x4F,0x50,0xBD,0xC3,0xF6,0xAF,0x02,0xA4,
-    0x64,0xBB,0xBC,0xFC,0xF9,0x82,0x28,0xCA,0x4B,0x0F,0x41,0xC0,
-    0x24,0xD3,0xE7,0x3F,0x7E,0x28,0x5F,0x6F,0xE3,0xAA,0xB0,0xF1,
-    0x7A,0x93,0xE4,0x71,0xD5,0xF3,0xBB,0x16,0x16,0x51,0x90,0x71,
-    0x51,0x6A,0xFA,0x91,0x24,0x03,0x69,0x0F,0x8A,0x49,0x0A,0x67,
-    0xF5,0xFF,0x08,0x27,0x29,0x08,0x05,0x7B
+  static unsigned char dh2048_p[] = {
+    0x8E, 0x68, 0x75, 0xB9, 0x01, 0xDD, 0x4D, 0xFC, 0x4E, 0xCB,
+    0x11, 0x1B, 0x28, 0x05, 0x77, 0xD1, 0xF5, 0x1F, 0xCE, 0xA3,
+    0x03, 0x17, 0xF0, 0xA1, 0x3F, 0x38, 0xDF, 0xCB, 0x39, 0x76,
+    0x8D, 0xCA, 0xEA, 0x40, 0xC8, 0x6B, 0x93, 0xBE, 0xA8, 0xD8,
+    0xD3, 0xCD, 0x5E, 0xAC, 0x47, 0xC2, 0xC7, 0x5D, 0x31, 0x9D,
+    0x51, 0xCE, 0xF5, 0x3C, 0xFE, 0x39, 0x7E, 0xBA, 0x14, 0x6E,
+    0x3D, 0x68, 0xD7, 0x08, 0x56, 0x5B, 0x84, 0x44, 0xF8, 0x37,
+    0x5B, 0xEB, 0xBE, 0x26, 0x4C, 0xDD, 0x52, 0x61, 0x57, 0xC3,
+    0xCF, 0x1E, 0xE8, 0x95, 0x38, 0x00, 0x8E, 0xCB, 0x7D, 0xA3,
+    0x15, 0xDF, 0x92, 0xCF, 0x1E, 0x1B, 0xA3, 0x67, 0x17, 0x48,
+    0xAF, 0x37, 0x84, 0x9E, 0xA3, 0x45, 0xDF, 0xB4, 0x6A, 0xC3,
+    0xF5, 0x6B, 0x05, 0xA3, 0xCF, 0xDF, 0xF4, 0xE9, 0xD1, 0x64,
+    0xAC, 0x82, 0xC2, 0x5C, 0xC2, 0x1F, 0x40, 0xBA, 0x34, 0x0F,
+    0xCA, 0xEA, 0x9A, 0x9A, 0x67, 0x11, 0xF0, 0xC3, 0x03, 0x0B,
+    0xAE, 0x74, 0x2A, 0x4C, 0xF6, 0x47, 0x03, 0x98, 0x14, 0x40,
+    0x9B, 0xD2, 0x6C, 0x29, 0xB4, 0x3A, 0x83, 0x36, 0x56, 0x8E,
+    0x47, 0x39, 0xF9, 0x05, 0x92, 0x69, 0x0A, 0x1F, 0xA2, 0x32,
+    0x07, 0x6E, 0x3B, 0xE3, 0xDF, 0x1C, 0xE0, 0xB9, 0xA0, 0x89,
+    0x9F, 0xEA, 0x10, 0xBC, 0x75, 0x8C, 0xFA, 0x1B, 0x00, 0x9D,
+    0xA3, 0xA0, 0x13, 0x00, 0xB2, 0x79, 0x9D, 0xF1, 0xAA, 0xCF,
+    0xBF, 0xE6, 0x5C, 0x12, 0x6E, 0x41, 0x3F, 0xB6, 0xA2, 0x56,
+    0xF7, 0xC7, 0x04, 0x64, 0x6C, 0xA0, 0x05, 0x45, 0x68, 0xF6,
+    0x3C, 0x59, 0x45, 0x9C, 0x7A, 0x28, 0xE7, 0xE3, 0xA5, 0xDA,
+    0xDB, 0xC9, 0xE9, 0xCE, 0xF4, 0xB2, 0x6B, 0xFE, 0xAB, 0x72,
+    0xAD, 0x90, 0x77, 0xD5, 0x62, 0x5B, 0xAB, 0x12, 0x34, 0x9B,
+    0x40, 0x0A, 0x4C, 0x03, 0xBC, 0x53
   };
-  static unsigned char dh1024_g[] = { 0x02 };
+  static unsigned char dh2048_g[] = { 0x02 };
 
   DH *dh;
+#if !(OPENSSL_VERSION_NUMBER < 0x10100005L || defined(LIBRESSL_VERSION_NUMBER))
+  BIGNUM *p, *g;
+#endif
+
   dh = DH_new();
 
 #if OPENSSL_VERSION_NUMBER < 0x10100005L || defined(LIBRESSL_VERSION_NUMBER)
-  dh->p = BN_bin2bn(dh1024_p, sizeof(dh1024_p), NULL);
-  dh->g = BN_bin2bn(dh1024_g, sizeof(dh1024_g), NULL);
+  dh->p = BN_bin2bn(dh2048_p, sizeof(dh2048_p), NULL);
+  dh->g = BN_bin2bn(dh2048_g, sizeof(dh2048_g), NULL);
 
   if ((dh->p == NULL) || (dh->g == NULL)) {
     DH_free(dh);
     return NULL;
   }
 #else
-  BIGNUM *p, *g;
-  p = BN_bin2bn(dh1024_p, sizeof(dh1024_p), NULL);
-  g = BN_bin2bn(dh1024_g, sizeof(dh1024_g), NULL);
+  p = BN_bin2bn(dh2048_p, sizeof(dh2048_p), NULL);
+  g = BN_bin2bn(dh2048_g, sizeof(dh2048_g), NULL);
 
   if (p == NULL || g == NULL || !DH_set0_pqg(dh, p, NULL, g)) {
     DH_free(dh);
@@ -139,7 +160,7 @@ static int engine_verify_callback(int preverify_ok, X509_STORE_CTX* ctx) {
 }
 
 VALUE engine_init_server(VALUE self, VALUE mini_ssl_ctx) {
-  VALUE obj;
+  VALUE obj, session_id_bytes;
   SSL_CTX* ctx;
   SSL* ssl;
   int min, ssl_options;
@@ -198,7 +219,7 @@ VALUE engine_init_server(VALUE self, VALUE mini_ssl_ctx) {
   else {
     min = TLS1_VERSION;
   }
-  
+
   SSL_CTX_set_min_proto_version(ctx, min);
 
   SSL_CTX_set_options(ctx, ssl_options);
@@ -226,7 +247,21 @@ VALUE engine_init_server(VALUE self, VALUE mini_ssl_ctx) {
     SSL_CTX_set_cipher_list(ctx, "HIGH:!aNULL@STRENGTH");
   }
 
-  DH *dh = get_dh1024();
+  // Random.bytes available in Ruby 2.5 and later, Random::DEFAULT deprecated in 3.0
+  session_id_bytes = rb_funcall(
+#ifdef HAVE_RANDOM_BYTES
+    rb_cRandom,
+#else
+    rb_const_get(rb_cRandom, rb_intern_const("DEFAULT")),
+#endif
+    rb_intern_const("bytes"),
+    1, ULL2NUM(SSL_MAX_SSL_SESSION_ID_LENGTH));
+
+  SSL_CTX_set_session_id_context(ctx,
+                                 (unsigned char *) RSTRING_PTR(session_id_bytes),
+                                 SSL_MAX_SSL_SESSION_ID_LENGTH);
+
+  DH *dh = get_dh2048();
   SSL_CTX_set_tmp_dh(ctx, dh);
 
 #if OPENSSL_VERSION_NUMBER < 0x10002000L
@@ -493,27 +528,27 @@ void Init_mini_ssl(VALUE puma) {
 #else
   rb_define_const(mod, "OPENSSL_LIBRARY_VERSION", rb_str_new2(SSLeay_version(SSLEAY_VERSION)));
 #endif
- 
-#if defined(OPENSSL_NO_SSL3) || defined(OPENSSL_NO_SSL3_METHOD) 
-  /* True if SSL3 is not available */ 
-  rb_define_const(mod, "OPENSSL_NO_SSL3", Qtrue); 
-#else 
-  rb_define_const(mod, "OPENSSL_NO_SSL3", Qfalse); 
-#endif 
-
-#if defined(OPENSSL_NO_TLS1) || defined(OPENSSL_NO_TLS1_METHOD) 
-  /* True if TLS1 is not available */ 
-  rb_define_const(mod, "OPENSSL_NO_TLS1", Qtrue); 
-#else 
-  rb_define_const(mod, "OPENSSL_NO_TLS1", Qfalse); 
-#endif 
-
-#if defined(OPENSSL_NO_TLS1_1) || defined(OPENSSL_NO_TLS1_1_METHOD) 
-  /* True if TLS1_1 is not available */ 
-  rb_define_const(mod, "OPENSSL_NO_TLS1_1", Qtrue); 
-#else 
-  rb_define_const(mod, "OPENSSL_NO_TLS1_1", Qfalse); 
-#endif 
+
+#if defined(OPENSSL_NO_SSL3) || defined(OPENSSL_NO_SSL3_METHOD)
+  /* True if SSL3 is not available */
+  rb_define_const(mod, "OPENSSL_NO_SSL3", Qtrue);
+#else
+  rb_define_const(mod, "OPENSSL_NO_SSL3", Qfalse);
+#endif
+
+#if defined(OPENSSL_NO_TLS1) || defined(OPENSSL_NO_TLS1_METHOD)
+  /* True if TLS1 is not available */
+  rb_define_const(mod, "OPENSSL_NO_TLS1", Qtrue);
+#else
+  rb_define_const(mod, "OPENSSL_NO_TLS1", Qfalse);
+#endif
+
+#if defined(OPENSSL_NO_TLS1_1) || defined(OPENSSL_NO_TLS1_1_METHOD)
+  /* True if TLS1_1 is not available */
+  rb_define_const(mod, "OPENSSL_NO_TLS1_1", Qtrue);
+#else
+  rb_define_const(mod, "OPENSSL_NO_TLS1_1", Qfalse);
+#endif
 
   rb_define_singleton_method(mod, "check", noop, 0);
 
diff --git a/test/test_puma_server_ssl.rb b/test/test_puma_server_ssl.rb
index 1329a1d969..dc5f02254d 100644
--- a/test/test_puma_server_ssl.rb
+++ b/test/test_puma_server_ssl.rb
@@ -94,7 +94,8 @@ def test_request_wont_block_thread
     ctx = OpenSSL::SSL::SSLContext.new
     ctx.verify_mode = OpenSSL::SSL::VERIFY_NONE
     socket = OpenSSL::SSL::SSLSocket.new TCPSocket.new(@host, @port), ctx
-    socket.write "x"
+    socket.connect
+    socket.write "HEAD"
     sleep 0.1
 
     # Capture the amount of threads being used after connecting and being idle