Depends how you draw your lines and whether you consider highs and lows as valid data points or as outliers and just consider the open and close. And then depending on which start point you choose it either broke down through the bottom of the up channel yesterday evening (yellow squiggly arrow) or early morning the day before.
Another factor to consider is that it has made a lower high midday yesterday (circled red) and a lower low (circled white). From my perspective, which is extremely inexperienced, the gbp/chf on the H4 is not any longer in an up trend. But the Fibonacci people may also point out it has retraced to 61.8 of the H/L and may be finding support.
The acid test will be to see if the price finds resistance against that lower trendline. If it does that might suggest it has broken down. If it doesn't, a resumption of the uptrend has a higher probability.