See the data version history.
The data of old versions are not available at WDCGG.

Updated Date	Version * : the latest version	GAW ID	Station/Mobile	Gas Species † met : with meteorological data	Platform	Sampling Type	Buffer	Organization	Details
2021-04-30	0020-4004-1103-01-02-9999 -2021-04-30-1104*	CHL	Churchill	C18O2	surface	flask	data1	ECCC (Environment and Climate Change Canada)	click
2019-10-15	0020-4004-1103-01-02-9999 -2019-09-30-2318	CHL	Churchill	C18O2	surface	flask	data1	ECCC (Environment and Climate Change Canada)
2019-09-03	0020-4004-1103-01-02-9999 -2019-09-02-1446	CHL	Churchill	C18O2	surface	flask	data1	ECCC (Environment and Climate Change Canada)
2018-06-08	0020-4004-1103-01-02-9999 -2018-02-28-1132	CHL	Churchill	C18O2	surface	flask	data1	ECCC (Environment and Climate Change Canada)