There is no such circular posted at icai.org, and generally icai.org does not change dates for state elections. Also in case of any changes it is more likely to be postponed. The date in the examination forms should be considered final unless otherwise updated in the admit card and/ or announced at icai.org later.
The dates at present has been announced here:
https://220.227.161.86/21408notifi12191.pdf
Also, it was never announced to be 12th April nor 26th April. It is from 2nd May to 16th May, every alternate day. Rely more on information posted at icai.org than other websites/ text messages.