Turnover Limits for Requirement of Registration Under GST

Sir
1.one of my client is getting approx 2 lakhs rent per month, what are the current limit for registration in GST as i heard GST limit is increased to 40 lakhs, if GST is necessary for 20 lakhs turnover, when we should apply for GST as it will cross the turnover of 20.lakhs in Dec or january so can we apply in the month when it reaches the limit or it is neccasary to apply immediately

2.and if GST limit increased to 40 lakhs can we show 24 lakhs rent and 15 lakhs other goods and services sales without registering into GST

My client location is in Hyderabad, Telangana

Thanks in advance