diff --git a/Hlt/RecoConf/python/RecoConf/hlt1_allen.py b/Hlt/RecoConf/python/RecoConf/hlt1_allen.py
index efce1697f9a24d82bd59f58622aff02db84363bf..68588e3ab6e8ac71ce6193d23faae3e22750a976 100644
--- a/Hlt/RecoConf/python/RecoConf/hlt1_allen.py
+++ b/Hlt/RecoConf/python/RecoConf/hlt1_allen.py
@@ -169,12 +169,9 @@ def make_allen_velo_tracks():
     velo_states = allen_reco['velo_states']
 
     velo_tracks_v2 = GaudiAllenVeloToV2Tracks(
-        AllenVeloTrackOffsets=velo_tracks["dev_offsets_all_velo_tracks"],
-        AllenVeloTrackHitOffsets=velo_tracks[
-            "dev_offsets_velo_track_hit_number"],
-        AllenVeloTrackHits=velo_tracks["dev_velo_track_hits"],
-        AllenVeloKalmanStates=velo_states["dev_velo_kalman_beamline_states"]
-    ).OutputTracks
+        allen_velo_tracks_mec=velo_tracks["dev_imec_velo_tracks"],
+        allen_velo_states_view=velo_states[
+            "dev_velo_kalman_beamline_states_view"]).OutputTracks
 
     velo_tracks_v1 = FromV2TrackV1Track(
         InputTracksName=velo_tracks_v2).OutputTracksName
@@ -201,26 +198,16 @@ def make_allen_velo_ut_tracks():
     allen_reco = hlt1_reconstruction()
 
     # Velo reconstruction
-    velo_tracks = allen_reco["velo_tracks"]
     velo_states = allen_reco["velo_states"]
     # UT reconstruction
     ut_tracks = allen_reco["ut_tracks"]
 
     ut_tracks_v2 = GaudiAllenUTToV2Tracks(
-        offsets_all_velo_tracks=velo_tracks["dev_offsets_all_velo_tracks"],
-        offsets_velo_track_hit_number=velo_tracks[
-            "dev_offsets_velo_track_hit_number"],
-        velo_track_hits=velo_tracks["dev_velo_track_hits"],
-        velo_kalman_beamline_states=velo_states[
-            "dev_velo_kalman_beamline_states"],
-        velo_kalman_endvelo_states=velo_states[
-            "dev_velo_kalman_endvelo_states"],
-        atomics_ut=ut_tracks["dev_offsets_ut_tracks"],
-        ut_track_hit_number=ut_tracks["dev_offsets_ut_track_hit_number"],
-        ut_qop=ut_tracks["dev_ut_qop"],
-        ut_track_velo_indices=ut_tracks["dev_ut_track_velo_indices"],
-        ut_track_hits=ut_tracks["dev_ut_track_hits"],
-    ).OutputTracks
+        allen_ut_tracks_mec=ut_tracks["dev_imec_ut_tracks"],
+        allen_beamline_states_view=velo_states[
+            "dev_velo_kalman_beamline_states_view"],
+        allen_endvelo_states_view=velo_states[
+            "dev_velo_kalman_endvelo_states_view"]).OutputTracks
 
     ut_tracks_v1 = FromV2TrackV1Track(
         InputTracksName=ut_tracks_v2).OutputTracksName
@@ -268,7 +255,7 @@ def make_allen_seed_and_match_tracks_no_ut():
     Configures the adaptor between the seed and match tracks reconstructed in
     Allen and Gaudi-LHCb tracks.
     """
-    from PyConf.Algorithms import GaudiAllenSeedAndMatchNoUTToV2Tracks
+    from PyConf.Algorithms import GaudiAllenForwardToV2Tracks
 
     allen_gaudi_node()  # Configure Allen sequence and apply bindings
 
@@ -276,28 +263,9 @@ def make_allen_seed_and_match_tracks_no_ut():
     allen_reco = hlt1_reconstruction(
         tracking_type=TrackingType.MATCHING, with_ut=False)
 
-    # Velo reconstruction
-    velo_tracks = allen_reco["velo_tracks"]
-    # SciFi reconstruction
-    seed_tracks = allen_reco["seeding_tracks"]
-    seed_and_match_tracks = allen_reco["long_tracks"]
-    # Kalman forward output
-    kalman_velo_only = allen_reco["kalman_velo_only"]
-
-    seed_and_match_tracks_v2 = GaudiAllenSeedAndMatchNoUTToV2Tracks(
-        offsets_all_velo_tracks=velo_tracks["dev_offsets_all_velo_tracks"],
-        offsets_velo_track_hit_number=velo_tracks[
-            "dev_offsets_velo_track_hit_number"],
-        velo_track_hits=velo_tracks["dev_velo_track_hits"],
-        atomics_scifi=seed_and_match_tracks["dev_offsets_long_tracks"],
-        scifi_track_hit_number=seed_and_match_tracks[
-            "dev_offsets_scifi_track_hit_number"],
-        scifi_track_hits=seed_and_match_tracks["dev_scifi_track_hits"],
-        scifi_track_velo_indices=seed_and_match_tracks[
-            "dev_scifi_track_ut_indices"],  # sic: see comment in AllenConf/matching_reconstruction.py: naming convention same as in forward so that hlt1 sequence works
-        scifi_qop=seed_tracks["dev_seeding_qop"],
-        scifi_states=seed_and_match_tracks["dev_scifi_states"],
-        kf_tracks=kalman_velo_only["dev_kf_tracks"]).OutputTracks
+    seed_and_match_tracks_v2 = GaudiAllenForwardToV2Tracks(
+        allen_tracks_mec=allen_reco['long_track_particles']
+        ['dev_multi_event_basic_particles']).OutputTracks
 
     seed_and_match_tracks_v1 = FromV2TrackV1Track(
         InputTracksName=seed_and_match_tracks_v2).OutputTracksName