diff --git a/Tests/Unit/Protocol/BPDReparseTest.php b/Tests/Unit/Protocol/BPDReparseTest.php
new file mode 100644
index 00000000..27cee6e0
--- /dev/null
+++ b/Tests/Unit/Protocol/BPDReparseTest.php
@@ -0,0 +1,66 @@
+<?php
+
+namespace Fhp\Tests\Unit\Protocol;
+
+use Fhp\FinTs;
+use Fhp\Options\Credentials;
+use Fhp\Options\FinTsOptions;
+use Fhp\Protocol\BPD;
+use Fhp\Segment\AnonymousSegment;
+use Fhp\Segment\HIBPA\HIBPAv3;
+use Fhp\Segment\KKU\DIKKUSv2;
+use Fhp\Syntax\Parser;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * A persisted BPD keeps the segments in the shape the library version that received them could parse. Segments that
+ * were unknown back then are stored as AnonymousSegment and stay that way after a library upgrade, because the bank
+ * only resends the BPD when it bumps the BPD version. Here DIKKUS (credit card statements) plays the role of the
+ * newly implemented segment.
+ */
+class BPDReparseTest extends TestCase
+{
+    private const RAW_DIKKUS = "DIKKUS:45:2:3+1+1+0+90:N:J'";
+    private const RAW_UNKNOWN = "HIXYZS:46:1:3+1+1+0+N'";
+
+    public function testReparsesSegmentsTheLibraryNowImplements()
+    {
+        $bpd = self::bpdWithAnonymousSegments();
+        $this->assertNull($bpd->getLatestSupportedParameters('DIKKUS'));
+
+        $bpd->reparseAnonymousSegments();
+
+        /** @var DIKKUSv2 $dikkus */
+        $dikkus = $bpd->getLatestSupportedParameters('DIKKUS');
+        $this->assertInstanceOf(DIKKUSv2::class, $dikkus);
+        $this->assertSame(90, $dikkus->getParameter()->speicherzeitraum);
+        // Still unknown segments are left alone.
+        $this->assertInstanceOf(AnonymousSegment::class, $bpd->parameters['HIXYZS'][1]);
+    }
+
+    public function testPersistedInstanceIsReparsedOnLoad()
+    {
+        $options = new FinTsOptions();
+        $options->url = 'https://bank.example/fints';
+        $options->bankCode = '12345678';
+        $options->productName = 'TEST';
+        $options->productVersion = '1.0';
+        $credentials = Credentials::create('user', 'pin');
+
+        $persisted = serialize([2, self::bpdWithAnonymousSegments(), null, null, null, null, null, null, 1]);
+        $fints = FinTs::new($options, $credentials, $persisted);
+
+        $this->assertInstanceOf(DIKKUSv2::class, $fints->getBpd()->getLatestSupportedParameters('DIKKUS'));
+    }
+
+    private static function bpdWithAnonymousSegments(): BPD
+    {
+        $bpd = new BPD();
+        $bpd->hibpa = HIBPAv3::parse("HIBPA:4:3:3+10+280:12345678+Testbank+1+1+300+500'");
+        $dikkus = Parser::parseAnonymousSegment(self::RAW_DIKKUS);
+        $unknown = Parser::parseAnonymousSegment(self::RAW_UNKNOWN);
+        $bpd->parameters['DIKKUS'][$dikkus->getVersion()] = $dikkus;
+        $bpd->parameters['HIXYZS'][$unknown->getVersion()] = $unknown;
+        return $bpd;
+    }
+}
diff --git a/src/FinTs.php b/src/FinTs.php
index aac493e6..1ee0ecd9 100644
--- a/src/FinTs.php
+++ b/src/FinTs.php
@@ -235,6 +235,11 @@ private function loadPersistedInstanceVersion2(array $data): void
             $this->dialogId,
             $this->messageNumber,
         ) = $data;
+
+        // The persisted BPD may predate segments that this library version implements.
+        if ($this->bpd !== null) {
+            $this->bpd->reparseAnonymousSegments();
+        }
     }
 
     /** @noinspection PhpUnused */
diff --git a/src/Protocol/BPD.php b/src/Protocol/BPD.php
index ec9fbd30..44b969ce 100644
--- a/src/Protocol/BPD.php
+++ b/src/Protocol/BPD.php
@@ -11,6 +11,7 @@
 use Fhp\Segment\SegmentInterface;
 use Fhp\Segment\TAN\HITANS;
 use Fhp\Segment\VPP\HIVPPSv1;
+use Fhp\Syntax\Parser;
 
 /**
  * Segmentfolge: Bankparameterdaten (Version 3)
@@ -70,6 +71,27 @@ public function getBankCode()
         return $this->hibpa->kreditinstitutskennung->kreditinstitutscode;
     }
 
+    /**
+     * Parses parameter segments again that were stored as {@link AnonymousSegment} because the library version that
+     * received them did not implement them yet. Persisted BPD survive library upgrades (the bank only resends the BPD
+     * when *its* version changes), so without this, a business transaction that a newer library version supports
+     * would still look unsupported to {@link getLatestSupportedParameters()} until the bank happens to bump the BPD.
+     */
+    public function reparseAnonymousSegments(): void
+    {
+        foreach ($this->parameters as $type => $versions) {
+            foreach ($versions as $version => $segment) {
+                if (!$segment instanceof AnonymousSegment) {
+                    continue;
+                }
+                $reparsed = Parser::detectAndParseSegment((string) $segment);
+                if (!$reparsed instanceof AnonymousSegment) {
+                    $this->parameters[$type][$version] = $reparsed;
+                }
+            }
+        }
+    }
+
     public function getBankName()
     {
         return $this->hibpa->kreditinstitutsbezeichnung;