Very good, this!
'Wicked Little Letters' is fun. Olivia Colman and Jessie Buckley impress in lead roles, both managing to stand out just as much as the other - Colman is particularly perfectly cast. The rest of them merit praise as well, namely Anjana Vasan and Timothy Spall.
There isn't much more to note about this really and I don't mean that in a negative way whatsoever. It's all competently put together, as those onscreen bring this rather simple film to life - and I like those type of movies. Well worth a watch!