EPSG:11156

COORDINATEOPERATION["NN54 height to NN2000 height (1)",
    VERSION["SK-Nor 2018"],
    SOURCECRS[
        VERTCRS["NN54 height",
            VDATUM["Norway Normal Null 1954"],
            CS[vertical,1],
                AXIS["gravity-related height (H)",up,
                    LENGTHUNIT["metre",1]],
            ID["EPSG",5776]]],
    TARGETCRS[
        VERTCRS["NN2000 height",
            DYNAMIC[
                FRAMEEPOCH[2000]],
            VDATUM["Norway Normal Null 2000"],
            CS[vertical,1],
                AXIS["gravity-related height (H)",up,
                    LENGTHUNIT["metre",1]],
            ID["EPSG",5941]]],
    METHOD["Vertical Offset by Grid Interpolation (gtx)",
        ID["EPSG",1084]],
    PARAMETERFILE["Vertical offset file","NNTrans2018B.gtx"],
    INTERPOLATIONCRS[
        GEOGCRS["ETRS89-NOR [EUREF89]",
            DATUM["ETRS89-NOR [EUREF89]",
                ELLIPSOID["GRS 1980",6378137,298.257222101,
                    LENGTHUNIT["metre",1]],
                ANCHOREPOCH[1995]],
            PRIMEM["Greenwich",0,
                ANGLEUNIT["degree",0.0174532925199433]],
            CS[ellipsoidal,2],
                AXIS["geodetic latitude (Lat)",north,
                    ORDER[1],
                    ANGLEUNIT["degree",0.0174532925199433]],
                AXIS["geodetic longitude (Lon)",east,
                    ORDER[2],
                    ANGLEUNIT["degree",0.0174532925199433]]]],
    OPERATIONACCURACY[0.03],
    USAGE[
        SCOPE["Change of height to a different vertical reference surface."],
        AREA["Norway - onshore."],
        BBOX[57.9,4.39,71.24,31.32]],
    ID["EPSG",11156]]

proj4.defs("EPSG:11156","+proj=vgridshift +grids=NNTrans2018B.gtx +multiplier=1");

{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "Transformation",
    "name": "NN54 height to NN2000 height (1)",
    "source_crs": {
        "type": "VerticalCRS",
        "name": "NN54 height",
        "datum": {
            "type": "VerticalReferenceFrame",
            "name": "Norway Normal Null 1954"
        },
        "coordinate_system": {
            "subtype": "vertical",
            "axis": [
                {
                    "name": "Gravity-related height",
                    "abbreviation": "H",
                    "direction": "up",
                    "unit": "metre"
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 5776
        }
    },
    "target_crs": {
        "type": "VerticalCRS",
        "name": "NN2000 height",
        "datum": {
            "type": "DynamicVerticalReferenceFrame",
            "name": "Norway Normal Null 2000",
            "frame_reference_epoch": 2000
        },
        "coordinate_system": {
            "subtype": "vertical",
            "axis": [
                {
                    "name": "Gravity-related height",
                    "abbreviation": "H",
                    "direction": "up",
                    "unit": "metre"
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 5941
        }
    },
    "interpolation_crs": {
        "type": "GeographicCRS",
        "name": "ETRS89-NOR [EUREF89]",
        "datum": {
            "type": "GeodeticReferenceFrame",
            "name": "ETRS89-NOR [EUREF89]",
            "anchor_epoch": 1995,
            "ellipsoid": {
                "name": "GRS 1980",
                "semi_major_axis": 6378137,
                "inverse_flattening": 298.257222101
            }
        },
        "coordinate_system": {
            "subtype": "ellipsoidal",
            "axis": [
                {
                    "name": "Geodetic latitude",
                    "abbreviation": "Lat",
                    "direction": "north",
                    "unit": "degree"
                },
                {
                    "name": "Geodetic longitude",
                    "abbreviation": "Lon",
                    "direction": "east",
                    "unit": "degree"
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 10875
        }
    },
    "method": {
        "name": "Vertical Offset by Grid Interpolation (gtx)",
        "id": {
            "authority": "EPSG",
            "code": 1084
        }
    },
    "parameters": [
        {
            "name": "Vertical offset file",
            "value": "NNTrans2018B.gtx",
            "id": {
                "authority": "EPSG",
                "code": 8732
            }
        }
    ],
    "accuracy": "0.03",
    "scope": "Change of height to a different vertical reference surface.",
    "area": "Norway - onshore.",
    "bbox": {
        "south_latitude": 57.9,
        "west_longitude": 4.39,
        "north_latitude": 71.24,
        "east_longitude": 31.32
    },
    "id": {
        "authority": "EPSG",
        "code": 11156
    }
}

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=vgridshift +grids=NNTrans2018B.gtx +multiplier=1">
	<Layer srs="+proj=vgridshift +grids=NNTrans2018B.gtx +multiplier=1">
	</Layer>
</Map>

INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) values ( 11156, 'EPSG', 11156, '+proj=vgridshift +grids=NNTrans2018B.gtx +multiplier=1', 'None');