New in version 6.9:

Database access 

Has now been completely overhauled. This means that model parameters can be read from a MySQL database in Linux, and reading them from an ODBC source such as .xls works in 64-bit Windows. .xlsb, .xlsm and .xlsx formats can also be used, and the data logger tool can write to any of these in Windows and to MySQL in Linux

New 'order' function 

Allows arrays to be sorted efficiently

2-D Shape Layers

2-D layers visualization now includes 2-D versions of the 3-D shapes from the projection viewer

Models as Maps

Components in a flat model can now represent components in an instance of a grid submodel according to their position on the diagram

Images on diagrams

There is now an image component that allows arbitrary images to be placed on the model diagram

New in version 6.4:

Generic 3-D shapes visualization tool

Display model data as lines, spheres or ellipses, and view as current lollipop diagram

New in version 6.2:

Data logger

Record values of several variables over time to a single file

Units for time series indices

e.g., 20*min to apply one reading every 20 minutes of simulated time

New in version 6.1:

Special-purpose submodels

Pre-defined submodel types for rectangular and hexagonal grid cells which allow communication between neighbours without the use of an association submodel

element() function works on lists

It can have a list as the first argument, and a single value, array or list as the second, allowing sublists of values to be picked from variable-membership submodels

Base instance lookup on more submodel types

A 2-dimensional array submodel, or a variable membership (including population) submodel can now have its indices looked up when building an association involving it

Layered display tool

Maps of different model values and a new tool for drawing widgets representing moving individuals can be superimposed or juxtaposed within one window, along with text and static images

New in version 6.0:

Discrete-event based modelling

Simile can now model systems in which instantaneous changes take place at arbitrary times, alongside continuous processes

Diagram-defined functions

Modellers can create functions to use in Simile equations by making model fragments that implement their behaviour

​Save and re-run editing sessions

Jump forwards and backwards between pre-defined points, for presentation or training

New in version 5.0:

Direct loading of grid data

Load 2-dimensional parameter arrays from comma-separated grids, image files or other datafile formats

Saving raw data in scenario files

Keep all the parameter information in one place, and have models start up faster

Following influences round the diagram

Simile v5 makes it easy to show, and follow, the way information flows round the model

with_greatest(...) and with_least(...) functions

New functions allowing data from special submodel instances to be picked out

Adaptive step size variation

Get more accurate results more quickly in 'stiff system' problem domains

There are a lot of other improvements, most of which do not require the modeller to do anything differently; see What's new in Simile 5.0, 5.1, etc for a more comprehensive list.

Happy modelling!