Root Sliver — ruling 1

Abilities that Slivers grant, as well as power/toughness boosts, are cumulative. However, for some abilities, like flying, having more than one instance of the ability doesn’t provide any additional benefit.

Root Sliver — ruling 2

If the creature type of a Sliver changes so it’s no longer a Sliver, it will no longer be affected by its own ability. Its ability will continue to affect other Sliver creatures.

Root Sliver — ruling 3

The first ability applies when this card is not on the battlefield. The second ability applies when this card is on the battlefield.

Root Sliver : règles, fonctionnement et interactions (MTG)

Root Sliver is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

This spell can't be countered. Sliver spells can't be countered.

How it works : Root Sliver

Original English text — Wizards of the Coast / Scryfall

#1July 1, 2013· Wizards of the Coast
Abilities that Slivers grant, as well as power/toughness boosts, are cumulative. However, for some abilities, like flying, having more than one instance of the ability doesn’t provide any additional benefit.
No other card is named in this ruling.
#2July 1, 2013· Wizards of the Coast
If the creature type of a Sliver changes so it’s no longer a Sliver, it will no longer be affected by its own ability. Its ability will continue to affect other Sliver creatures.
No other card is named in this ruling.
#3October 4, 2004· Wizards of the Coast
The first ability applies when this card is not on the battlefield. The second ability applies when this card is on the battlefield.
No other card is named in this ruling.