Wikipedia isn't authoritative, of course, but it is cited often. The legend at the top defines the terms used, but I could change the term "deprecated" to something else if it would be helpful.

I added the status column awhile back to encourage people to use the Area/Locality forms of names instead of the older ones. I just added some additional notes to the ones Manjusri cited to suggest alternatives.

From: tz <tz-bounces@iana.org> on behalf of Paul Eggert <eggert@cs.ucla.edu>
Sent: Tuesday, May 7, 2019 12:00 PM
To: Manjusri Mahendran -X (manjmahe - INFOSYS LIMITED at Cisco)
Cc: Time Zone Mailing List
Subject: Re: [tz] Issue with EST timezone

On 5/7/19 3:53 AM, Manjusri Mahendran -X (manjmahe - INFOSYS LIMITED at
Cisco) wrote:
>
> We have issues on Call Manager running on EST timezone.
>
> Could see that there is no replacement added for deprecated timezones
> EST, HST and MST whereas other deprecated timezones such as “Brazil
> East” and “Singapore” has a replacement.
>
> How are these three timezones different from the rest of deprecated ones.?

They aren't deprecated. EST, HST, and MST are still in tzdb, in the
'northamerica' file. They've been there since 2005. It sounds like
you've run into an issue that is downstream from tzdb.