When you unpack theme for e107 2.3.1, you can see:

- e107 plugins folder

- e107 themes folder

e107 themes folder contains 2 themes: hestia-core  and hestia itself.  If you plan to customize Hestia, it is recommended to rename this folder.

e107 plugins folder contains 2 plugins: JM Layouts and JM Elements. You should install theme before theme installation.

The welcome message is not supported in this theme by default. 

The welcome message is hidden on the homepage layout.

{WMESSAGE=hide}

If you want to use it, you can use {WMESSAGE=force} inside the needed element.

This theme solves the introduction header different way. 

Hestia is a Gaia theme with changed colors.  It was built for version 2.2 with tons of custom solutions, workarounds. During the time many of those ideas were moved to the core itself. 

It wouldn't problem, Hestia followed those changes. The real problem was a change during 2.3.1 development. You can't use the plugin anymore to extend layout functionality, because constant for information of the actual layout is not available in global shortcodes. 

Hestia 1.1.x  -  version for e107 2.2. This version works with version 2.3.0, but not with version 2.3.1. The latest supported version is version 1.1.1. This version uses JMElements and JMTheme plugins.

Hestia 1.2.x  - version for e107 2.3.0 only. This version prepares Hestia for core version 2.3.1. You should use this version ONLY if you have live site running with your data and maybe your customization.  If you don't update for version 2.3.0, you will not able to use the core 2.3.1 version.  There are steps on how to update... there are versions 1.2.0, 1.2.1, 1.2.2  and you should go one by one to don't kill your site.  Version 1.2.2 uses the new plugin JMLayouts that is the replacement of the JMTheme plugin.  

You should contact me, but definitely do update before updating core.

Hestia 2.0 - version prepared for 2.3.0 (HTML layouts), but it is not compatible with version 2.3.1 

Hestia 2.1 - version for e107 2.3.1 only.  In progress.