Comparison

R21 vs AVACAST Tx

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

R21

Features
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R21 is a new six-level reading series carefully designed to help young learners develop the skills they’ll need to succeed in the 21st century. Each book covers a range of topics and makes use of the latest Content and Language Integrated Learning (CLIL) methods to ensure they’ll appeal to young children and have a connection to children’s wider studies and experiences. With R21, reading is fun, inspiring as well as informative, and children will not only develop their reading competence but also become a great thinker in the 21st century.

About

AVACAST Tx

Features
Read full description

The AVACAST Tx app provides additional controls and features for users who want to cast or mirror their screens while using AVA OnCollab devices. This app unlocks the full potential of your OnCollab unit, enabling you to collaborate in your workspace or classrooms like never before.

Screenshots

R213 screens
AVACAST Tx3 screens

Verdict

The call

The clearest difference is iOS requirement: R21 at 9.0 against AVACAST Tx's 16.0. On price, update cadence, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 3 months. The most recent releases landed on November 2, 2026 and November 4, 2026 respectively.

Scorecard1 real difference · 5 level
R21 versus AVACAST Tx: the parameters behind the verdict, then further details
ParameterR21AVACAST Tx
PriceFreeFree
Update frequencyEvery 3 monthsEvery 3 months
AdsNoNo
In-app purchasesNoNo
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS9.0 — better16.0
Further details — not scored
Size114 MB25 MB
Age rating4+4+
DeveloperCAVES BOOKS LTD.禾麟數碼科技股份有限公司

In-app purchases

None

R21

No in-app purchases

None

AVACAST Tx

No in-app purchases

Questions

Is R21 free?
R21 is free to download, with no in-app purchases.
Is AVACAST Tx free?
AVACAST Tx is free to download, with no in-app purchases.
Do R21 or AVACAST Tx have ads?
Neither R21 nor AVACAST Tx shows ads.
Which is updated more often, R21 or AVACAST Tx?
R21 ships an update every 3 months, and AVACAST Tx every 3 months. Most recently, R21 was updated on November 2, 2026 and AVACAST Tx on November 4, 2026.

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