# Changing MesSy Version

URL: https://irs.systems/en/docs/ltt/documentation/ltt-gui-manual/configuration/messyconfiguration/changing-messy-version

The new LTT software can be used with both **MesSy V2** and **MesSy V1**. During installation you have to choose for one option but you can switch to the other MesSy version at any time afterwards.

> Before you setup the MesSy version in LTT software make sure that LTT GUI is closed.

To switch from one MesSy version to the other you need to perform some configuration changes in different places. The following table describes those changes.

| Location of change    | What to change                                            |
| --------------------- | --------------------------------------------------------- |
| ltt\_main\_config.xml | Change the parameter `<MessyVersion>X</MessyVersion>` to: |

```
- 1 for MesSy V1
- 2 for MesSy V2 |
```

\| ltt\_messy\_config.xml | The MesSy signal mapping file has a different format for MesSy V2 compared to MesSy V1.

You will find an example signal configuration for MesSy V1 here: `50_LTT_SW\LTT TS\examples\ltt_messy_config_V1.xml`

You will find an example signal configuration for MesSy V2 here: `50_LTT_SW\LTT TS\examples\ltt_messy_config_V2.xml`

Depending on what you have chosen during installation, one of those signal configuration files is copied to `50_LTT_SW\LTT Config\ltt_messy_config.xml` for use in a LTT testplan.

If you want to create a testplan for the other version of MesSy, simply copy the corresponding MesSy signal configuration file from `50_LTT_SW\LTT TS\examples\` to `50_LTT_SW\LTT Config\ltt_messy_config.xml`. | | LTT Template.seq | With the LTT installer there comes a LTT template sequence file - one for each MesSy version.

You will find the LTT template sequence file for MesSy V1 here: `50_LTT_SW\LTT TS\lib\IRS.MesSy\V1\LTT Template.seq`

You will find the LTT template sequence file for MesSy V2 here: `50_LTT_SW\LTT TS\lib\IRS.MesSy\LTT Template.seq`

Depending on what you have chosen during installation, one of those template sequence files is copied to `50_LTT_SW\LTT TS\LTT Template.seq`.

If you want to create a testplan for the other version of MesSy, simply copy the corresponding template sequence file to `50_LTT_SW\LTT TS\LTT Template.seq`. | | [LTT GUI - Project Wizard (F3)](../../LTTGUI/Dialogs/F3projectwizard/) | Open the project wizard in LTT GUI and go to [Test Station Configuration](/en/docs/ltt/documentation/ltt-gui-manual/lttgui/dialogs/f3projectwizard/teststationconfiguration). Read the corresponding chapter for more informations. |

> For TestStand integration read chapter [MesSy Integration](/en/docs/ltt/documentation/ltt-gui-manual/teststand/messyintegration).