As WhatsApp has decided to end support for some operating systems, telegram has also followed the trend by discontinuing support for older version of android operating systems. The total number of people still using android version 3.0 and below is about 19.6million all over the world which might give the developer issues when new features comes up.
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What this actually means is that; android Os lower than 4.0 will not support telegram again. The developer stated that the reason behind such actions is to enable them to implement newer version without having issues with Os compatibility.