keysend: deprecate in favor of `xkeysend`.

diff --git a/contrib/msggen/msggen/schema.json b/contrib/msggen/msggen/schema.json
index 8c86eeba..d65eaba7 100644
--- a/contrib/msggen/msggen/schema.json
+++ b/contrib/msggen/msggen/schema.json
@@ -17609,6 +17609,8 @@
       "rpc": "keysend",
       "title": "Send funds to a node without an invoice",
       "description": [
+        "WARNING: deprecated: use *xkeysend* which uses askrene for better route calculation (and learns from previous payments).",
+        "",
         "The **keysend** RPC command attempts to find a route to the given destination, and send the specified amount to it. Unlike the `pay` RPC command the `keysend` command does not require an invoice, instead it uses the `destination` node ID, and `amount` to find a route to the specified node.",
         "",
         "In order for the destination to be able to claim the payment, the `payment_key` is randomly generated by the sender and included in the encrypted payload for the destination. As a consequence there is not proof-of-payment, like there is with an invoice where the `payment_key` is generated on the destination, and the only way sender could have it is by sending a payment. Please ensure that this matches your use-case when using `keysend`.",
@@ -17826,6 +17828,7 @@
         "Christian Decker [decker@blockstream.com](mailto:decker@blockstream.com) is mainly responsible."
       ],
       "see_also": [
+        "lightning-xkeysend(7)",
         "lightning-listpays(7)",
         "lightning-decode(7)",
         "lightning-listinvoices(7)",
diff --git a/doc/developers-guide/deprecated-features.md b/doc/developers-guide/deprecated-features.md
index 89f75a4c..e20885f0 100644
--- a/doc/developers-guide/deprecated-features.md
+++ b/doc/developers-guide/deprecated-features.md
@@ -30,6 +30,7 @@ privacy:
 | pay                                                | Command            | v26.06           | v27.03         | Use the more sophisticated and effective "xpay" command instead (since v24.11).                                           |
 | paystatus                                          | Command            | v26.06           | v27.03         | Uses internal pay structures, doesn't work with xpay, doesn't work across restarts.                                       |
 | getroute                                           | Command            | v26.06           | v27.03         | Less flexible than `getroutes` which takes an actual fee budget and can do multiple paths at once.                        |
+| keysend                                            | Command            | v26.06           | v27.03         | Replaced by more powerful `xkeysend`.                                                                                     |
 
 Inevitably there are features which need to change: either to be generalized, or removed when they can no longer be supported.
 
diff --git a/doc/schemas/keysend.json b/doc/schemas/keysend.json
index fdb6615c..13d34a3b 100644
--- a/doc/schemas/keysend.json
+++ b/doc/schemas/keysend.json
@@ -4,6 +4,8 @@
   "rpc": "keysend",
   "title": "Send funds to a node without an invoice",
   "description": [
+    "WARNING: deprecated: use *xkeysend* which uses askrene for better route calculation (and learns from previous payments).",
+    "",
     "The **keysend** RPC command attempts to find a route to the given destination, and send the specified amount to it. Unlike the `pay` RPC command the `keysend` command does not require an invoice, instead it uses the `destination` node ID, and `amount` to find a route to the specified node.",
     "",
     "In order for the destination to be able to claim the payment, the `payment_key` is randomly generated by the sender and included in the encrypted payload for the destination. As a consequence there is not proof-of-payment, like there is with an invoice where the `payment_key` is generated on the destination, and the only way sender could have it is by sending a payment. Please ensure that this matches your use-case when using `keysend`.",
@@ -221,6 +223,7 @@
     "Christian Decker [decker@blockstream.com](mailto:decker@blockstream.com) is mainly responsible."
   ],
   "see_also": [
+    "lightning-xkeysend(7)",
     "lightning-listpays(7)",
     "lightning-decode(7)",
     "lightning-listinvoices(7)",
diff --git a/plugins/keysend.c b/plugins/keysend.c
index 92246bec..99495373 100644
--- a/plugins/keysend.c
+++ b/plugins/keysend.c
@@ -296,7 +296,8 @@ static struct command_result *json_keysend(struct command *cmd, const char *buf,
 static const struct plugin_command commands[] = {
     {
 	    "keysend",
-		json_keysend
+	    json_keysend,
+	    "v26.06", "v27.03",
     },
 };
 
diff --git a/tests/test_cln_rs.py b/tests/test_cln_rs.py
index dc6083c0..ea76002c 100644
--- a/tests/test_cln_rs.py
+++ b/tests/test_cln_rs.py
@@ -328,6 +328,7 @@ def test_grpc_keysend_routehint(bitcoind, node_factory):
     l1, l2, l3 = node_factory.line_graph(
         3,
         announce_channels=True,  # Do not enforce scid-alias
+        opts={'allow-deprecated-apis': True}
     )
     bitcoind.generate_block(3)
     sync_blockheight(bitcoind, [l1, l2, l3])
diff --git a/tests/test_misc.py b/tests/test_misc.py
index ab04418f..09a0974a 100644
--- a/tests/test_misc.py
+++ b/tests/test_misc.py
@@ -4865,7 +4865,8 @@ def test_preapprove(node_factory, bitcoind, preapprove):
 @pytest.mark.parametrize("xkeysend", [False, True])
 def test_preapprove_use(node_factory, bitcoind, xkeysend):
     """Test preapprove calls implicitly made by pay and keysend"""
-    l1, l2 = node_factory.line_graph(2, opts=[{}, {'dev-hsmd-fail-preapprove': None}])
+    l1, l2 = node_factory.line_graph(2, opts=[{}, {'dev-hsmd-fail-preapprove': None,
+                                                   'allow-deprecated-apis': True}])
 
     # Create some balance, make sure it's entirely settled.
     l1.pay(l2, 200000000)
diff --git a/tests/test_opening.py b/tests/test_opening.py
index a61cba10..918e37bb 100644
--- a/tests/test_opening.py
+++ b/tests/test_opening.py
@@ -2143,7 +2143,6 @@ def test_zeroreserve(node_factory, bitcoind):
 
     # Now do some drain tests on c1, as that should be drainable
     # completely by l2 being the fundee
-    l1.rpc.keysend(l2.info['id'], 10 * 7)  # Something above dust for sure
     l1.rpc.xkeysend(l2.info['id'], 10 * 7)  # Something above dust for sure
     l2.drain(l1)
 
diff --git a/tests/test_pay.py b/tests/test_pay.py
index 5059b0d0..eb52b860 100644
--- a/tests/test_pay.py
+++ b/tests/test_pay.py
@@ -3451,10 +3451,14 @@ def test_excluded_adjacent_routehint(node_factory, bitcoind):
 @pytest.mark.parametrize("keysendcmd", ["keysend", "xkeysend"])
 def test_keysend(node_factory, keysendcmd):
     amt = 10000
+    if keysendcmd == 'keysend':
+        opts = {'allow-deprecated-apis': True}
+    else:
+        opts = {}
     l1, l2, l3, l4 = node_factory.line_graph(
         4,
         wait_for_announce=True,
-        opts=[{}, {}, {}, {'disable-plugin': 'keysend'}]
+        opts=[opts, {}, opts, {'disable-plugin': 'keysend'}]
     )
 
     if keysendcmd == 'xkeysend':
@@ -3508,19 +3512,24 @@ def test_keysend_strip_tlvs(node_factory, keysendcmd):
     """Use the extratlvs option to deliver a message with sphinx' TLV type, which keysend strips.
     """
     amt = 10**7
+    opts = [
+        {
+            # Not needed, just for listconfigs test.
+            'accept-htlc-tlv-type': [133773310, 99990],
+            "plugin": os.path.join(os.path.dirname(__file__), "plugins/sphinx-receiver.py"),
+        },
+        {
+            "plugin": os.path.join(os.path.dirname(__file__), "plugins/sphinx-receiver.py"),
+        },
+    ]
+    if keysendcmd == 'keysend':
+        opts[0]['allow-deprecated-apis'] = True
+        opts[1]['allow-deprecated-apis'] = True
+
     l1, l2 = node_factory.line_graph(
         2,
         wait_for_announce=True,
-        opts=[
-            {
-                # Not needed, just for listconfigs test.
-                'accept-htlc-tlv-type': [133773310, 99990],
-                "plugin": os.path.join(os.path.dirname(__file__), "plugins/sphinx-receiver.py"),
-            },
-            {
-                "plugin": os.path.join(os.path.dirname(__file__), "plugins/sphinx-receiver.py"),
-            },
-        ]
+        opts=opts,
     )
 
     if keysendcmd == 'xkeysend':
@@ -3583,7 +3592,7 @@ def test_keysend_routehint(node_factory):
     """Test whether we can deliver a keysend by adding a routehint on the cli
     """
     amt = 10000
-    l1, l2 = node_factory.line_graph(2, wait_for_announce=True)
+    l1, l2 = node_factory.line_graph(2, wait_for_announce=True, opts={'allow-deprecated-apis': True})
     l3 = node_factory.get_node()
     l2.connect(l3)
     l2.fundchannel(l3, announce_channel=False)
@@ -3684,10 +3693,13 @@ def test_xkeysend_layer(node_factory):
 
 @pytest.mark.parametrize("keysendcmd", ["keysend", "xkeysend"])
 def test_keysend_maxfee(node_factory, keysendcmd):
+    opts = [{}, {'fee-base': 50, 'fee-per-satoshi': 0}, {}]
+    if keysendcmd == 'keysend':
+        opts[0]['allow-deprecated-apis'] = True
     l1, l2, l3 = node_factory.line_graph(
         3,
         wait_for_announce=True,
-        opts=[{}, {'fee-base': 50, 'fee-per-satoshi': 0}, {}]
+        opts=opts,
     )
 
     if keysendcmd == 'keysend':
@@ -3719,7 +3731,11 @@ def test_keysend_description_size_limit(node_factory, keysendcmd):
 
     See common/bolt11.h: BOLT11_FIELD_BYTE_LIMIT.
     """
-    l1, l2 = node_factory.line_graph(2, wait_for_announce=True)
+    if keysendcmd == 'keysend':
+        opts = {'allow-deprecated-apis': True}
+    else:
+        opts = {}
+    l1, l2 = node_factory.line_graph(2, wait_for_announce=True, opts=opts)
     amt = 10000
     prefix = 'keysend: '
     base_len = len(prefix)
@@ -4083,7 +4099,11 @@ def test_listpay_result_with_paymod(node_factory, bitcoind, keysendcmd):
     """
     amount_sat = 10 ** 6
 
-    l1, l2, l3 = node_factory.line_graph(3, wait_for_announce=True)
+    if keysendcmd == 'keysend':
+        opts = {'allow-deprecated-apis': True}
+    else:
+        opts = {}
+    l1, l2, l3 = node_factory.line_graph(3, wait_for_announce=True, opts=opts)
 
     invl2 = l2.rpc.invoice(amount_sat * 2, "inv_l2", "inv_l2")
     l1.rpc.pay(invl2['bolt11'])
diff --git a/tests/test_plugin.py b/tests/test_plugin.py
index 367b5bd0..87708885 100644
--- a/tests/test_plugin.py
+++ b/tests/test_plugin.py
@@ -450,13 +450,13 @@ def test_pay_plugin(node_factory):
 
 
 def test_keysend_plugin(node_factory):
-    l1, l2 = node_factory.line_graph(2)
+    l1, l2 = node_factory.line_graph(2, opts={'allow-deprecated-apis': True})
 
     with pytest.raises(RpcError, match=r'missing required parameter'):
         l1.rpc.call('keysend')
 
     # Make sure usage messages are present.
-    msg = 'keysend destination amount_msat [label] [maxfeepercent] [retry_for] '\
+    msg = 'keysend (DEPRECATED!) destination amount_msat [label] [maxfeepercent] [retry_for] '\
           '[maxdelay] [exemptfee] [extratlvs] [routehints] [maxfee]'
     # We run with --developer:
     msg += ' [dev_use_shadow]'