> For the complete documentation index, see [llms.txt](https://legacy-docs.aragon.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://legacy-docs.aragon.org/the-ant-token/antv1/antv1-non-standard-behaviours-and-gotchas.md).

# Non-standard behaviours and gotchas

{% hint style="warning" %}
On this page, you will find **specific behaviours encoded** into ANTv1 that may be useful to be aware of, even when not programmatically interacting with the contract.

> **This page contains technical information. It is provided for advanced users.**
> {% endhint %}

## Gas

Because ANTv1 includes historical balance records for each address, **token transfers are slightly more expensive** than some other tokens.

The exact amount per transfer will differ between hardfork environments and whether the receiver has previously held an ANTv1 balance before, but it is safe to **start with a gas limit of 150,000** and optimize lower over time.

## Changing non-zero allowances

The ANTv1 contract reverts when attempting to modify an allowance (calling `ANT.approve()`) that is not zero. [More details of the rationale behind this](https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729).

To successfully change an allowance in this circumstance, you must first ask the user to reset their allowance for that spender to zero (`ANT.approve(0)`), and then to the amount desired.

It is useful to note that this behaviour is considered non-standard for ERC20s, and may lead to problems if ANTv1 is used by a contract that is not designed to handle this behaviour.

## Initially vested tokens

The ANTv1 contract includes **specific functionality for whitelisted addresses** to create irrevocable time-based token vests by transferring tokens from their own balance.

Some token holders (founders, advisors, and early contributors) received tokens around the initial token sale that were granted in such a way to limit their transferability.

Although all such tokens are now vested and transferable in full, [this blog post](https://blog.aragon.org/a-note-for-exchanges-or-holders-interacting-with-ant-in-an-automated-manner-fe13152c1b36) may still be a useful historical resource for exchanges or other automated market makers interested in integrating with ANTv1. Note that this is not relevant for ANTv2.

## Receiving ETH

{% hint style="danger" %}
Sending ETH directly to the ANTv1 contract will revert. You should never have a reason to want to do this!
{% endhint %}