The Asterisk community has officially released Asterisk 21.0.0 for Asterisk users. It is one of the standard releases of this popular open-source VoIP telephony framework. If you are using any Asterisk based solution or offering Asterisk solution development, you must know about this crucial release of this telephony platform.

In this blog post, we are going to cover major details of Asterisk 21. You will learn about new features in this latest release. Moreover, you will learn some necessary facts to make the maximum out of this popular open-source VoIP platform.

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You must be excited to learn about Asterisk and Asterisk 21.0.0 in particular. Therefore, without any further delays, let’s move on to delve deeper into this interesting subject.

1. What is Asterisk?

In the VoIP industry, Asterisk is a popular telephony stack. Moreover, it is popular as a telephony kit because it provides a complete suite of features to build powerful telephony solutions. Additionally, it is an open-source VoIP framework. In short, you get access to this platform for free with a general public license (GPL).

According to the shared statistics by the official website of Asterisk, annually Asterisk has registered 2,000,000 downloads. Moreover, 1,000,000 servers are configured with this open-source platform. In addition to that, every year, 1,300,000 new endpoints are registered. Furthermore, across 170 countries across the world, Asterisk users are using this platform to meet their communication needs or to provide communication services using this platform.

Asterisk is also a popular open-source tool with 86,000 community members contributing to empowering this open-source platform in one way or another.

Asterisk is renowned as a pioneer platform to develop a telephony solution development platform. Originally, it was available as a PBX platform with all PBX features. However, now it is one of the most advanced platforms to build any type of telephony solution. For example, a VoIP Softphone, IP PBX solution, call center solution, fax server solution, class 4 Softswitch, and similar VoIP software are developed in Asterisk. Companies offering Asterisk development services also develop custom telephony solutions to meet the business needs of companies.

2. Asterisk Characteristics

Asterisk Application Development

There are multiple advantages of using this platform to build different types of telephony and communication solutions. There are multiple competitive technology stacks available in the market. However, Asterisk is still popular because of its powerful characteristics. Let’s take a look at the major ones.

Open Source

Asterisk is an open-source VoIP framework. This characteristic makes it one of the most convenient platforms. Asterisk was the first open-source telephony stack. There is a huge community of 86,000 members. In short, it is one of the most powerful open-source platforms. Moreover, its active community members persistently make changes and improvements to this platform. For example, frequent releases of Asterisk versions are classic examples of the dedication of these community members.


Asterisk is a complete telephony suite with a range of communication features. The right Asterisk development company will use these core features to develop a custom telephony solution. It supports all control features like Auto attendant, call transfer, call forwarding, call queuing, call snooping, call monitoring, call recording, call parking, ENUM support, music on hold, and more. In addition to communication features, it also supports voicemail, SMS, fax, and more. In short, you can develop an omnichannel or multichannel solution.


Originally, Asterisk was built for Linux-based systems only. However, with the advanced releases of this platform, it has started supporting all different operating systems, devices, and platforms. Moreover, it also supports different sets of codecs.

For example, it supports ADPCM, G.711, G.722, G.726, GSM, Speex, Ilbc, CELT, and more. In addition, it also supports all traditional telephony protocols and ISDN protocols. In short, Asterisk is a highly flexible platform. Therefore, the possibility of building a powerful telephony solution using Asterisk solution development is abundant.

Read our blog post on, Impeccable Benefits of Custom Asterisk Development Services. You will learn how a tailored development process helps in building the most powerful telephony solution.


The scalability of any software solution is crucial for a business. When we are discussing communication and collaboration platforms, it becomes even more important to use a scalable solution. Asterisk is a very powerful platform to build a highly scalable solution. Moreover, you can create cluster architecture to ensure high scalability along with high availability.

Cost Effective

Asterisk is an open-source telephony software development framework. Therefore, it is available for free. In short, you don’t need to pay any fee to use Asterisk for your telephony network setup.

If you have expertise in developing Asterisk platforms, then you will need to invest nothing more than your time in developing or setting up your telephony network. However, if you don’t know coding practice, then you can hire an expert to contract a company. In this case, you need to pay the development cost.

Asterisk has been in the industry for decades. Therefore, you will find ample options to develop your telephony solution. Therefore, you will not need to worry about cost because there is competition in the industry. As a result, cost-effective development is possible.

Vendor Independence

Asterisk provides you access to the code. Therefore, you are not dependent on any single vendor. You can simply switch to another company or developer if you are unhappy with your existing partner. Similarly, there are several other advantages of using this platform due to its vendor-independent characteristics.

3. Understanding Asterisk 21

The Asterisk community has released a steady version of Asterisk 21.0.0. You can download it from any of the following sources:

a. GitHub Download Link

b. Asterisk Website Download Link

According to shared details, this version has majorly addressed comments and feedback shared by community members. Moreover, it has introduced several new features. In addition to that, this new version has removed several deprecated modules, applications, and features. Furthermore, it has fixed major performance bugs.

  • Let’s take a look at the vital changes in the latest Asterisk version:
  • Multiple functionalities to remove different deprecated modules
  • Features to clean JIRA and Gerrit references
  • AsteriskReleaser update for high security
  • Fixed different anchor references
  • Fixed different issues related to loops. For example, infinite loop at the time of sending digits, for loop declaration, etc.
  • Fixed compiler warning for different functions
  • Fixed different version-related issues and concerns
  • Prefix argument is possible to make optional
  • Changes in CHANGE and UPGRADE files
  • Analog users can use called subscriber help feature

In addition to all these major changes, more than 15 known or reported bugs are fixed by team Asterisk.

If you are interested in learning details of all major changes brought by Asterisk 21, then here is the Changelog link. In addition to the Changelog, this link also shares details of bug numbers and details that are addressed in Asterisk 21.0.0.

4. Major Reasons to Upgrade to Asterisk 21

Asterisk Development Services

According to industry experts, using the most recent version of any technology platform is always great. In the case of Asterisk as well, it is recommended to use the latest version, which is Asterisk 21.0.0.

Let us share the major reasons to use Asterisk 21.

More Powerful Platform

Certainly, Asterisk 21 is much more powerful than its earlier versions. It has several new features. Moreover, it has removed several unwanted features and modules. Furthermore, it is a major standard release, unlike minor changes in the earlier version. Therefore, Asterisk 21 provides a powerful tool to build any custom telephony stack. Furthermore, it also increases features for an existing telephony app developed using Asterisk.

Access to Advanced Features

As mentioned earlier, Asterisk 21 has some major new features. Moreover, it has added compatibility for some platforms that were not available in earlier Asterisk versions. Therefore, by upgrading to the latest version, you will get access to advanced and never-used features. In addition to that, an Asterisk development company can think of building custom communication solutions with advanced features.

Added Stability

A majority of version releases add more stability to the platform. As a result, its users can receive better-quality solutions and features. This is the case with Asterisk 21, too. Therefore, you can enjoy better stability and related benefits by using the latest version of Asterisk or by upgrading to it.

Get Rid of Bugs

Bugs are major concerns for developers. Moreover, known yet unresolved platform bugs often become a major drawback for development companies because developers can’t get rid of these bugs. As a result, users face some challenges and bad experiences. However, by upgrading to the latest version of Asterisk, you can get rid of several known bugs. This helps in getting rid of issues occurring due to these bugs. Moreover, the removal of bugs makes the platform more lightweight for users. As a result, better performance and quality service are easily achievable.

5. Challenges in Upgrading to Asterisk 21

Two major challenges that you may face while upgrading the version of Asterisk. Therefore, it is necessary to understand these challenges and how you can overcome them.

Lack of Technical Expertise

It is pretty simple to upgrade to Asterisk 21 if you have the required expertise in the technical aspects of Asterisk. However, if you do not have technical knowledge, then it will be difficult to upgrade the version because it would be a long learning curve. However, you can take the help of a company or developer that can help you with their technical expertise to make the upgrade process seamless.

Some Modules or Features Stop Working

Generally, the Asterisk software development process considers the existing version. Therefore, the software is developed accordingly. However, when you upgrade the version, some features may stop working and those will need a fix. Therefore, it is necessary to keep this aspect in mind. Moreover, there has to be a plan to ensure the system doesn’t stop working completely. In addition to that, if it stops working, then there has to be a plan to recover as soon as possible.

6. Tips to Upgrade

Asterisk Solution Development

It is always great to make a plan for a successful upgrade. It will keep you prepared for the upcoming challenges. As a result, you can easily manage these challenges.

Take Backup

The first piece of advice is to keep yourself prepared to face catastrophe. You need to know what to do if your upgrade fails. Therefore, you must take a backup, which you can upload to use existing settings if your upgrade process fails.

Take Expert Help

If you don’t have expertise in upgrading the Asterisk version, then don’t play around with a live system. Certainly, you must hire an expert for an upgrade. Moreover, you can also keep an expert on standby. As a result, in case you get stuck at a certain point, you can get the immediate help of the expert.

Keep Documentation and Support Handy

Certainly, it is easy to upgrade to Asterisk 21.0.0. However, if you don’t have experience, then it is always good to keep documentation and external help ready. You can also delegate this job to multiple engineers as they can make the whole process flawless.

7. Major Services We Offer in Asterisk 21

We are renowned for our Asterisk development services and products. We have a team of experienced developers and support engineers in Asterisk. We offer multiple services specific to the Asterisk 21 version such as:

  • Version upgrade
  • Asterisk software development in Asterisk 21
  • Migration to Asterisk 21
  • Technical support
  • Consultation


In conclusion, Asterisk 21 is a more robust and feature rich version of Asterisk. Therefore, it is a good idea to upgrade to this latest Asterisk version. However, you must keep the major facts shared in this blog post in mind.

We are renowned for our services in Asterisk. Furthermore, we have a range of offerings in Asterisk 21. To learn more about Asterisk solution development and Asterisk 21 related services, contact us.