Makefile: update next and prev versions now we've released.

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 28557a9..6088499 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -299,8 +299,8 @@ jobs:
         run: |
           mkdir /tmp/old-cln
           cd /tmp/old-cln
-          wget https://github.com/ElementsProject/lightning/releases/download/v25.09/clightning-v25.09-ubuntu-24.04-amd64.tar.xz
-          tar -xaf clightning-v25.09-ubuntu-24.04-amd64.tar.xz
+          wget https://github.com/ElementsProject/lightning/releases/download/v25.12/clightning-v25.12-ubuntu-24.04-amd64.tar.xz
+          tar -xaf clightning-v25.12-ubuntu-24.04-amd64.tar.xz
 
       - name: Switch network
         if: ${{ matrix.TEST_NETWORK == 'liquid-regtest' }}
diff --git a/Makefile b/Makefile
index 5b5f33b..a5ab6dc 100644
--- a/Makefile
+++ b/Makefile
@@ -7,10 +7,10 @@ VERSION ?= $(shell git describe --tags --always --dirty=-modded --abbrev=7 2>/de
 $(info Building version $(VERSION))
 
 # Next release.
-CLN_NEXT_VERSION := v25.12
+CLN_NEXT_VERSION := v26.04
 
 # Previous release (for downgrade testing)
-CLN_PREV_VERSION := v25.09
+CLN_PREV_VERSION := v25.12
 
 # --quiet / -s means quiet, dammit!
 ifeq ($(findstring s,$(word 1, $(MAKEFLAGS))),s)
diff --git a/tests/test_downgrade.py b/tests/test_downgrade.py
index e460f3d..939aa99 100644
--- a/tests/test_downgrade.py
+++ b/tests/test_downgrade.py
@@ -84,7 +84,8 @@ def test_downgrade(node_factory, executor):
     # Should be able to upgrade without any trouble
     l1.daemon.opts['database-upgrade'] = True
     l1.start()
-    assert l1.daemon.is_in_log("Updating database from version")
+    # Note: currently a noop, this will break on first database upgrade.
+    assert not l1.daemon.is_in_log("Updating database from version 280")
 
     l1.connect(l2)
     inv2 = l2.rpc.invoice(1000, 'test_downgrade2', 'test_downgrade2')
@@ -96,8 +97,8 @@ def test_downgrade(node_factory, executor):
     assert bias['bias'] == 1
 
 
-def test_downgrade_fail(node_factory, executor):
-    """If we have created as node bias, we cannot downgrade"""
+def test_downgrade_bias(node_factory, executor):
+    """If we have created as node bias, we *can* downgrade this version."""
     l1, l2 = node_factory.line_graph(2, opts={'may_reconnect': True}, wait_for_announce=True)
 
     l1.rpc.askrene_bias_node('xpay', l2.info['id'], 'in', 1)
@@ -108,5 +109,4 @@ def test_downgrade_fail(node_factory, executor):
     p = subprocess.Popen(cmd_line, stdout=subprocess.DEVNULL,
                          stderr=subprocess.PIPE)
     _, err = p.communicate(timeout=TIMEOUT)
-    assert p.returncode == ERROR_DBFAIL
-    assert 'Askrene has a node bias, which is not supported in v25.09' in err.decode('utf-8')
+    assert p.returncode == 0
diff --git a/tests/test_pay.py b/tests/test_pay.py
index 06b8281..18bd3e1 100644
--- a/tests/test_pay.py
+++ b/tests/test_pay.py
@@ -6082,8 +6082,8 @@ def test_fetch_no_description_with_amount(node_factory):
 
 def test_decodepay(node_factory, chainparams):
     """Test we don't break (deprecated) decodepay command"""
-    l1 = node_factory.get_node(options={'allow-deprecated-apis': True},
-                               broken_log="DEPRECATED API USED decodepay")
+    l1 = node_factory.get_node(options={'allow-deprecated-apis': True,
+                                        'i-promise-to-fix-broken-api-user': 'decodepay'})
 
     addr1 = l1.rpc.newaddr('bech32')['bech32']
     addr2 = '2MxqzNANJNAdMjHQq8ZLkwzooxAFiRzXvEz' if not chainparams['elements'] else 'XGx1E2JSTLZLmqYMAo3CGpsco85aS7so33'
diff --git a/tests/test_plugin.py b/tests/test_plugin.py
index 6e2a94f..b50a347 100644
--- a/tests/test_plugin.py
+++ b/tests/test_plugin.py
@@ -4177,9 +4177,9 @@ def test_sql(node_factory, bitcoind):
 def test_sql_deprecated(node_factory, bitcoind):
     l1, l2 = node_factory.line_graph(2, opts=[{'allow-deprecated-apis': True}, {}])
 
-    # l1 allows it, l2 doesn't
-    ret = l1.rpc.sql("SELECT max_total_htlc_in_msat FROM peerchannels;")
-    assert ret == {'rows': [[-1]]}
+    # Even with deprecated APIs, this isn't there.
+    with pytest.raises(RpcError, match="Deprecated column table peerchannels.max_total_htlc_in_msat"):
+        l1.rpc.sql("SELECT max_total_htlc_in_msat FROM peerchannels;")
 
     # It's deprecated in l2, so that will fail!
     with pytest.raises(RpcError, match="Deprecated column table peerchannels.max_total_htlc_in_msat"):
diff --git a/tests/test_xpay.py b/tests/test_xpay.py
index 08219de..e576d15 100644
--- a/tests/test_xpay.py
+++ b/tests/test_xpay.py
@@ -674,12 +674,12 @@ def test_xpay_no_mpp(node_factory, chainparams):
 
 @pytest.mark.parametrize("deprecations", [False, True])
 def test_xpay_bolt12_no_mpp(node_factory, chainparams, deprecations):
-    """In deprecated mode, we use MPP even if BOLT12 invoice doesn't say we should"""
+    """If we force it, we use MPP even if BOLT12 invoice doesn't say we should"""
     # l4 needs dev-allow-localhost so it considers itself to have an advertized address, and doesn't create a blinded path from l2/l4.
     opts = [{}, {}, {'dev-force-features': -17, 'dev-allow-localhost': None}, {}]
     if deprecations is True:
         for o in opts:
-            o['allow-deprecated-apis'] = True
+            o['i-promise-to-fix-broken-api-user'] = 'xpay.ignore_bolt12_mpp'
             o['broken_log'] = 'DEPRECATED API USED: xpay.ignore_bolt12_mpp'
 
     l1, l2, l3, l4 = node_factory.get_nodes(4, opts=opts)
diff --git a/tools/lightning-downgrade.c b/tools/lightning-downgrade.c
index 6b52dff..3bf41c6 100644
--- a/tools/lightning-downgrade.c
+++ b/tools/lightning-downgrade.c
@@ -168,7 +168,7 @@ static const char *downgrade_askrene_layers(const tal_t *ctx, struct db *db)
 
 static const struct db_version db_versions[] = {
 	{ "v25.09", 276, downgrade_askrene_layers, false },
-	/* When we implement v25.12 downgrade: { "v25.12", 280, ???}, */
+	{ "v25.12", 280, NULL, true },
 };
 
 static const struct db_version *version_db(const char *version)