4 months between tier 1 e expire n 10 yrs

hello
My tier 1 e visa expire in April 2017 n my 10 years in uk finish on 1st sept 2017.
What's the best thing to do ?

Best to go for extension, doesn't matter if you go for ILR they might ask you all the relevant documents of visa, you were granted previously, otherwise if HO rejects your ILR 10 year, you might not get right of appeal due to your current leave to remain.

I m in the same situation like u, I am going to keep up with the requirements of current visa and will go for extension and that seems to be only option there. If the extension was still under process at the time when u will hit 10 year long stay Then u can very your application and submit the one based on 10 year long residency. This way you will get right of appeal in any unfortunate event.