Heat exchanger (100;200;300;400;500;600) for heat exchange between a first medium and a second medium, comprising a main inlet (101;201;301;401;501;601) for the first medium; a main outlet (102;202;302;402;502;602) for the first medium; and a plurality of heat exchanging plates (110;210;310), the plates (110;210;310) being associated with a main plane of extension and a height direction perpendicular to said main plane, and in turn comprising a respective first heat transfer surface (114;214;314) on a first side (113;213;313) of the plate (110;210;310), arranged to be in contact with the first medium flowing along said first side (113;213;313); a respective second heat transfer surface (116;216;316) on a second side (115;215;315) of the plate (110;210;310), arranged to be in contact with the second medium flowing along said second side (115;215;315); a respective plurality of indentations (120,130,140;220,230,240;320,330,340) in the plate (110;210;310), formed by the material of the plate (110;210;310) bulging out locally in the said plate height direction, the plates (110;210;310) being stacked together so as to form a heat exchanger heat plate stack, wherein the plates (110;210;310) comprise respective ridge-shaped indentations (120;220;320), in turn arranged to form, together with a corresponding ridge-shaped indentation of an adjacent plate in said stack, at least one respective closed flow channel (105',105";205';305',305") for the first medium with a general flow direction, wherein the said closed channel (105',105";205';305',305") comprises a floor (105a;205a;305a) and a ceiling (105b;205b;305c), as viewed in the height direction, and wherein the closed channel (105',105";205';305',305") comprises a step (105c;205c;305c) in the height direction along said general flow direction by the said floor (105a;205a;305a) and said ceiling (105b;205b;305b) both being offset in same height direction, characterised in that the plates additionally comprise a plurality of bridge-shaped indentations (130;230;330), formed to comprise a respective through hole (132a,132b;232a,232b;332a,332b) through the plate in question and arranged to form, together with a corresponding bridge-shaped indentation (130;230;330) of an adjacent plate in said stack, an open flow channel (106;206;306) for the second medium. a main inlet (101;201;301;401;501;601) for the first medium; a main outlet (102;202;302;402;502;602) for the first medium; and a plurality of heat exchanging plates (110;210;310), the plates (110;210;310) being associated with a main plane of extension and a height direction perpendicular to said main plane, and in turn comprising a respective first heat transfer surface (114;214;314) on a first side (113;213;313) of the plate (110;210;310), arranged to be in contact with the first medium flowing along said first side (113;213;313); a respective second heat transfer surface (116;216;316) on a second side (115;215;315) of the plate (110;210;310), arranged to be in contact with the second medium flowing along said second side (115;215;315); a respective plurality of indentations (120,130,140;220,230,240;320,330,340) in the plate (110;210;310), formed by the material of the plate (110;210;310) bulging out locally in the said plate height direction, the plates (110;210;310) being stacked together so as to form a heat exchanger heat plate stack, wherein the plates (110;210;310) comprise respective ridge-shaped indentations (120;220;320), in turn arranged to form, together with a corresponding ridge-shaped indentation of an adjacent plate in said stack, at least one respective closed flow channel (105',105";205';305',305") for the first medium with a general flow direction, wherein the said closed channel (105',105";205';305',305") comprises a floor (105a;205a;305a) and a ceiling (105b;205b;305c), as viewed in the height direction, and wherein the closed channel (105',105";205';305',305") comprises a step (105c;205c;305c) in the height direction along said general flow direction by the said floor (105a;205a;305a) and said ceiling (105b;205b;305b) both being offset in same height direction, characterised in that the plates additionally comprise a plurality of bridge-shaped indentations (130;230;330), formed to comprise a respective through hole (132a,132b;232a,232b;332a,332b) through the plate in question and arranged to form, together with a corresponding bridge-shaped indentation (130;230;330) of an adjacent plate in said stack, an open flow channel (106;206;306) for the second medium.